Improve _accept length check by radarhere · Pull Request #9170 · python-pillow/Pillow · GitHub

This improves/adds length checks in _accept for several plugins.

Here are two examples of the errors this fixes.

>>> from PIL import FliImagePlugin
>>> FliImagePlugin._accept(b"test\x11\xaf")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "PIL/FliImagePlugin.py", line 35, in _accept
    and i16(prefix, 14) in [0, 3]  # flags
  File "PIL/_binary.py", line 37, in i16le
    return unpack_from("<H", c, o)[0]
struct.error: unpack_from requires a buffer of at least 16 bytes for unpacking 2 bytes at offset 14 (actual buffer size is 6)
>>> from PIL import GribStubImagePlugin
>>> GribStubImagePlugin._accept(b"GRIB")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "PIL/GribStubImagePlugin.py", line 36, in _accept
    return prefix.startswith(b"GRIB") and prefix[7] == 1
IndexError: index out of range

This PR contains the following updates: | Package | Change | Age | Confidence | |---|---|---|---| | [pillow](https://github.com/python-pillow/Pillow) ([changelog](https://github.com/python-pillow/Pillow/releases)) | `<12.0.0,>=11.0.0` -> `<12.0.1,>=12.0.0` | [![age](https://developer.mend.io/api/mc/badges/age/pypi/pillow/12.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/pypi/pillow/11.3.0/12.0.0?slim=true)](https://docs.renovatebot.com/merge-confidence/) | --- ### Release Notes <details> <summary>python-pillow/Pillow (pillow)</summary> ### [`v12.0.0`](https://github.com/python-pillow/Pillow/releases/tag/12.0.0) [Compare Source](python-pillow/Pillow@11.3.0...12.0.0) <https://pillow.readthedocs.io/en/stable/releasenotes/12.0.0.html> #### Removals - Remove support for FreeType <= 2.9.0 [#9159](python-pillow/Pillow#9159) \[[@radarhere](https://github.com/radarhere)] - Drop support for Python 3.9 [#9119](python-pillow/Pillow#9119) \[[@hugovk](https://github.com/hugovk)] - Remove deprecations for Pillow 12.0.0 [#9053](python-pillow/Pillow#9053) \[[@radarhere](https://github.com/radarhere)] #### Deprecations - Deprecate Image.\_show [#9186](python-pillow/Pillow#9186) \[[@radarhere](https://github.com/radarhere)] - Deprecate ImageCmsProfile product\_name and product\_info [#8995](python-pillow/Pillow#8995) \[[@lukegb](https://github.com/lukegb)] #### Documentation - ImagingHistogramInstance can use two bands [#9251](python-pillow/Pillow#9251) \[[@radarhere](https://github.com/radarhere)] - Update 12.0.0 release notes [#9247](python-pillow/Pillow#9247) \[[@hugovk](https://github.com/hugovk)] - Added ImageDraw alpha channel examples [#9201](python-pillow/Pillow#9201) \[[@radarhere](https://github.com/radarhere)] - Update Python version [#9230](python-pillow/Pillow#9230) \[[@radarhere](https://github.com/radarhere)] - Updated macOS tested Pillow versions [#9209](python-pillow/Pillow#9209) \[[@radarhere](https://github.com/radarhere)] - Add GitHub profile link to release notes [#9197](python-pillow/Pillow#9197) \[[@radarhere](https://github.com/radarhere)] - Split versionadded info [#9190](python-pillow/Pillow#9190) \[[@radarhere](https://github.com/radarhere)] - Document ImageFile.MAXBLOCK [#9163](python-pillow/Pillow#9163) \[[@radarhere](https://github.com/radarhere)] - Updated macOS version in CI targets [#9157](python-pillow/Pillow#9157) \[[@radarhere](https://github.com/radarhere)] - Fix typos [#9135](python-pillow/Pillow#9135) \[[@radarhere](https://github.com/radarhere)] - Added "Colors" to concepts [#9067](python-pillow/Pillow#9067) \[[@radarhere](https://github.com/radarhere)] - Update macOS tested Pillow versions [#9068](python-pillow/Pillow#9068) \[[@radarhere](https://github.com/radarhere)] - Thanks, folks! [#9056](python-pillow/Pillow#9056) \[[@aclark4life](https://github.com/aclark4life)] - Setup nit: "fork" should be lowercased [#9055](python-pillow/Pillow#9055) \[[@aclark4life](https://github.com/aclark4life)] #### Dependencies - Update dependency cibuildwheel to v3.2.1 [#9246](python-pillow/Pillow#9246) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - \[pre-commit.ci] pre-commit autoupdate [#9233](python-pillow/Pillow#9233) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Update harfbuzz to 12.1.0 [#9218](python-pillow/Pillow#9218) \[[@radarhere](https://github.com/radarhere)] - Update libtiff to 4.7.1 [#9222](python-pillow/Pillow#9222) \[[@radarhere](https://github.com/radarhere)] - Update FreeType to 2.14.1 on macOS and Linux wheels [#9217](python-pillow/Pillow#9217) \[[@radarhere](https://github.com/radarhere)] - Update dependency cibuildwheel to v3.2.0 [#9219](python-pillow/Pillow#9219) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update Ghostscript to 10.6.0 [#9202](python-pillow/Pillow#9202) \[[@radarhere](https://github.com/radarhere)] - Update openjpeg to 2.5.4 [#9215](python-pillow/Pillow#9215) \[[@radarhere](https://github.com/radarhere)] - Update harfbuzz to 11.5.0 [#9203](python-pillow/Pillow#9203) \[[@radarhere](https://github.com/radarhere)] - Update dependency mypy to v1.18.2 [#9213](python-pillow/Pillow#9213) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency mypy to v1.18.1 [#9207](python-pillow/Pillow#9207) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update github-actions [#9194](python-pillow/Pillow#9194) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Updated harfbuzz to 11.4.5 [#9150](python-pillow/Pillow#9150) \[[@radarhere](https://github.com/radarhere)] - Update zlib-ng to 2.2.5 [#9140](python-pillow/Pillow#9140) \[[@radarhere](https://github.com/radarhere)] - Update raqm to 0.10.3 [#9137](python-pillow/Pillow#9137) \[[@radarhere](https://github.com/radarhere)] - Update libjpeg-turbo to 3.1.2 [#9188](python-pillow/Pillow#9188) \[[@radarhere](https://github.com/radarhere)] - \[pre-commit.ci] pre-commit autoupdate [#9180](python-pillow/Pillow#9180) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Update dependency cibuildwheel to v3.1.4 [#9164](python-pillow/Pillow#9164) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update actions/checkout action to v5 [#9156](python-pillow/Pillow#9156) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update actions/download-artifact action to v5 [#9141](python-pillow/Pillow#9141) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Updated harfbuzz to 11.3.3 [#9103](python-pillow/Pillow#9103) \[[@radarhere](https://github.com/radarhere)] - \[pre-commit.ci] pre-commit autoupdate [#9131](python-pillow/Pillow#9131) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] - Updated libimagequant to 4.4.0 [#9074](python-pillow/Pillow#9074) \[[@radarhere](https://github.com/radarhere)] - Update dependency mypy to v1.17.1 [#9130](python-pillow/Pillow#9130) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency cibuildwheel to v3.1.3 [#9129](python-pillow/Pillow#9129) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency cibuildwheel to v3.1.2 [#9118](python-pillow/Pillow#9118) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Updated libpng to 1.6.50 [#9058](python-pillow/Pillow#9058) \[[@radarhere](https://github.com/radarhere)] - Update cygwin/cygwin-install-action action to v6 [#9108](python-pillow/Pillow#9108) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Update dependency mypy to v1.17.0 [#9092](python-pillow/Pillow#9092) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - Updated libwebp to 1.6.0 [#9082](python-pillow/Pillow#9082) \[[@radarhere](https://github.com/radarhere)] - Update dependency cibuildwheel to v3.0.1 [#9075](python-pillow/Pillow#9075) \[@[renovate\[bot\]](https://github.com/apps/renovate)] - \[pre-commit.ci] pre-commit autoupdate [#9073](python-pillow/Pillow#9073) \[@[pre-commit-ci\[bot\]](https://github.com/apps/pre-commit-ci)] #### Testing - Check return types [#9045](python-pillow/Pillow#9045) \[[@radarhere](https://github.com/radarhere)] - Upgrade from macos-13 [#9212](python-pillow/Pillow#9212) \[[@radarhere](https://github.com/radarhere)] - Wheels CI: Check number of expected dists [#9239](python-pillow/Pillow#9239) \[[@hugovk](https://github.com/hugovk)] - Assert image type [#8845](python-pillow/Pillow#8845) \[[@radarhere](https://github.com/radarhere)] - Test GD transparency [#9196](python-pillow/Pillow#9196) \[[@radarhere](https://github.com/radarhere)] - Test mode when saving PPM images [#9195](python-pillow/Pillow#9195) \[[@radarhere](https://github.com/radarhere)] - Test unsupported BMP bitfields layout [#9193](python-pillow/Pillow#9193) \[[@radarhere](https://github.com/radarhere)] - Update Ghostscript to 10.6.0 [#9202](python-pillow/Pillow#9202) \[[@radarhere](https://github.com/radarhere)] - Use monkeypatch [#9192](python-pillow/Pillow#9192) \[[@radarhere](https://github.com/radarhere)] - Always check XMLPacket value [#9113](python-pillow/Pillow#9113) \[[@radarhere](https://github.com/radarhere)] - Rename variable to not shadow import [#9124](python-pillow/Pillow#9124) \[[@radarhere](https://github.com/radarhere)] - Removed unused code [#9182](python-pillow/Pillow#9182) \[[@radarhere](https://github.com/radarhere)] - Add has\_feature\_version helper [#9172](python-pillow/Pillow#9172) \[[@radarhere](https://github.com/radarhere)] - Replace print with assert [#9171](python-pillow/Pillow#9171) \[[@radarhere](https://github.com/radarhere)] - Add Debian 13 Trixie [#9147](python-pillow/Pillow#9147) \[[@hugovk](https://github.com/hugovk)] - Do not import from Tests directory in checks [#9143](python-pillow/Pillow#9143) \[[@radarhere](https://github.com/radarhere)] - Improve features test coverage [#9077](python-pillow/Pillow#9077) \[[@radarhere](https://github.com/radarhere)] - Remove WebP feature handling [#9096](python-pillow/Pillow#9096) \[[@radarhere](https://github.com/radarhere)] - Update for pyroma 5.0 [#9093](python-pillow/Pillow#9093) \[[@radarhere](https://github.com/radarhere)] - Improve WmfImagePlugin test coverage [#9090](python-pillow/Pillow#9090) \[[@radarhere](https://github.com/radarhere)] - Improve DdsImagePlugin test coverage [#9091](python-pillow/Pillow#9091) \[[@radarhere](https://github.com/radarhere)] - Improve ImageMath test coverage [#9087](python-pillow/Pillow#9087) \[[@radarhere](https://github.com/radarhere)] - Fix unclosed file warning [#9065](python-pillow/Pillow#9065) \[[@radarhere](https://github.com/radarhere)] - Pyroma now supports PEP 639 [#9064](python-pillow/Pillow#9064) \[[@radarhere](https://github.com/radarhere)] #### Type hints - Install arro3 dependencies when type checking [#9254](python-pillow/Pillow#9254) \[[@radarhere](https://github.com/radarhere)] - Check return types [#9045](python-pillow/Pillow#9045) \[[@radarhere](https://github.com/radarhere)] - Assert image type [#8845](python-pillow/Pillow#8845) \[[@radarhere](https://github.com/radarhere)] - Move imports into TYPE\_CHECKING [#9123](python-pillow/Pillow#9123) \[[@radarhere](https://github.com/radarhere)] - Remove support for NumPy 1.20 when type checking [#9125](python-pillow/Pillow#9125) \[[@radarhere](https://github.com/radarhere)] #### Other changes - Use macos-14 for iOS arm64 simulator [#9258](python-pillow/Pillow#9258) \[[@hugovk](https://github.com/hugovk)] - Use enums for Modes and RawModes in C [#9256](python-pillow/Pillow#9256) \[[@radarhere](https://github.com/radarhere)] - Add ImageText [#9098](python-pillow/Pillow#9098) \[[@radarhere](https://github.com/radarhere)] - Shift bits before making value negative [#9255](python-pillow/Pillow#9255) \[[@radarhere](https://github.com/radarhere)] - Support saving variable length rational TIFF tags by default [#9241](python-pillow/Pillow#9241) \[[@radarhere](https://github.com/radarhere)] - Added four private SGI TIFF tags [#9245](python-pillow/Pillow#9245) \[[@radarhere](https://github.com/radarhere)] - Band names for arrow exported images [#9099](python-pillow/Pillow#9099) \[[@wiredfool](https://github.com/wiredfool)] - Use macos-latest for iOS arm64 simulator [#9250](python-pillow/Pillow#9250) \[[@radarhere](https://github.com/radarhere)] - If pasting an image onto itself at a lower position, copy from bottom [#8882](python-pillow/Pillow#8882) \[[@radarhere](https://github.com/radarhere)] - Removed unused access for I;32L and I;32B [#9238](python-pillow/Pillow#9238) \[[@radarhere](https://github.com/radarhere)] - Corrected scientific-python-nightly-wheels pattern [#9252](python-pillow/Pillow#9252) \[[@radarhere](https://github.com/radarhere)] - Run sdist when scheduled, but do not upload to scientific-python-nightly-wheels index [#9248](python-pillow/Pillow#9248) \[[@radarhere](https://github.com/radarhere)] - Removed shebang lines and executable flags [#9179](python-pillow/Pillow#9179) \[[@radarhere](https://github.com/radarhere)] - Remove Pillow version from PDF comment [#9176](python-pillow/Pillow#9176) \[[@radarhere](https://github.com/radarhere)] - Support saving variable length rational TIFF tags [#9111](python-pillow/Pillow#9111) \[[@radarhere](https://github.com/radarhere)] - Build Python 3.14 on macOS 10.15 [#9234](python-pillow/Pillow#9234) \[[@radarhere](https://github.com/radarhere)] - Test largest CUR cursor [#9191](python-pillow/Pillow#9191) \[[@radarhere](https://github.com/radarhere)] - Do not unnecessarily update FLI \_\_offset [#9184](python-pillow/Pillow#9184) \[[@radarhere](https://github.com/radarhere)] - Fill alpha channel when quantizing RGB images [#9133](python-pillow/Pillow#9133) \[[@radarhere](https://github.com/radarhere)] - Allow RGBA palettes to work with ImageOps.expand() [#9138](python-pillow/Pillow#9138) \[[@radarhere](https://github.com/radarhere)] - Fixed loading rotated PCD images [#9177](python-pillow/Pillow#9177) \[[@radarhere](https://github.com/radarhere)] - Cast before shifting bits [#9236](python-pillow/Pillow#9236) \[[@radarhere](https://github.com/radarhere)] - Use \_ensure\_mutable() [#9200](python-pillow/Pillow#9200) \[[@radarhere](https://github.com/radarhere)] - Seek past BeginBinary data when parsing EPS metadata [#9211](python-pillow/Pillow#9211) \[[@radarhere](https://github.com/radarhere)] - Do not allow negative offset with memory mapping [#9235](python-pillow/Pillow#9235) \[[@radarhere](https://github.com/radarhere)] - Clear C image when MPO frame image size changes [#9208](python-pillow/Pillow#9208) \[[@radarhere](https://github.com/radarhere)] - When converting RGBA to PA, use RGB to P quantization [#9153](python-pillow/Pillow#9153) \[[@radarhere](https://github.com/radarhere)] - Remove use of sudo from libavif and raqm install scripts [#9231](python-pillow/Pillow#9231) \[[@radarhere](https://github.com/radarhere)] - Load image palette into Python after converting to PA [#9152](python-pillow/Pillow#9152) \[[@radarhere](https://github.com/radarhere)] - Check all reserved bytes in FLI header [#9183](python-pillow/Pillow#9183) \[[@radarhere](https://github.com/radarhere)] - Limit length of read operation in ImageFont.\_load\_pilfont\_data() [#9181](python-pillow/Pillow#9181) \[[@radarhere](https://github.com/radarhere)] - Python 3.9 wheels are no longer needed [#9214](python-pillow/Pillow#9214) \[[@radarhere](https://github.com/radarhere)] - Remove unused Image \_expand() [#9227](python-pillow/Pillow#9227) \[[@radarhere](https://github.com/radarhere)] - Updated FreeType to 2.14.1 on Windows [#9206](python-pillow/Pillow#9206) \[[@radarhere](https://github.com/radarhere)] - Only deprecate fromarray mode for changing data types [#9063](python-pillow/Pillow#9063) \[[@radarhere](https://github.com/radarhere)] - Fix reading RGB and CMYK IPTC images [#9088](python-pillow/Pillow#9088) \[[@radarhere](https://github.com/radarhere)] - Install zstd for libtiff on Linux wheels [#9097](python-pillow/Pillow#9097) \[[@radarhere](https://github.com/radarhere)] - Improve WalImageFile test coverage [#9189](python-pillow/Pillow#9189) \[[@radarhere](https://github.com/radarhere)] - ImageMorph operations must have length 1 [#9102](python-pillow/Pillow#9102) \[[@radarhere](https://github.com/radarhere)] - Set correct size for rotated PCD images after opening [#9086](python-pillow/Pillow#9086) \[[@radarhere](https://github.com/radarhere)] - Simplify check for GBR width and height [#9089](python-pillow/Pillow#9089) \[[@radarhere](https://github.com/radarhere)] - Make in parallel when building libjpeg-turbo and openjpeg for macOS and Linux wheels [#9144](python-pillow/Pillow#9144) \[[@radarhere](https://github.com/radarhere)] - Fix ZeroDivisionError in ImageStat [#9105](python-pillow/Pillow#9105) \[[@radarhere](https://github.com/radarhere)] - When deleting EXIF IFD tag, delete IFD data [#9083](python-pillow/Pillow#9083) \[[@radarhere](https://github.com/radarhere)] - Allow alpha\_composite to use LA images [#9066](python-pillow/Pillow#9066) \[[@radarhere](https://github.com/radarhere)] - Improve \_accept length check [#9170](python-pillow/Pillow#9170) \[[@radarhere](https://github.com/radarhere)] - Do not set core to DeferredError [#9166](python-pillow/Pillow#9166) \[[@radarhere](https://github.com/radarhere)] - Use macos-14 for iOS arm64 simulator [#9161](python-pillow/Pillow#9161) \[[@radarhere](https://github.com/radarhere)] - Make in parallel when building brotli and libavif for macOS and Linux wheels [#9142](python-pillow/Pillow#9142) \[[@radarhere](https://github.com/radarhere)] - Use Python 3.14 for gcc problem matching [#9134](python-pillow/Pillow#9134) \[[@radarhere](https://github.com/radarhere)] - Add libavif support for iOS [#9117](python-pillow/Pillow#9117) \[[@freakboy3742](https://github.com/freakboy3742)] - Restore pyroma test for iOS [#9116](python-pillow/Pillow#9116) \[[@freakboy3742](https://github.com/freakboy3742)] - Use correct bands for two band histograms [#9054](python-pillow/Pillow#9054) \[[@radarhere](https://github.com/radarhere)] - Add support for Python 3.14 [#9120](python-pillow/Pillow#9120) \[[@hugovk](https://github.com/hugovk)] - Drop support for PyPy3.10 [#9112](python-pillow/Pillow#9112) \[[@radarhere](https://github.com/radarhere)] - Add parallel compile from pybind11 [#8990](python-pillow/Pillow#8990) \[[@wiredfool](https://github.com/wiredfool)] - Remove unused \_save\_cjpeg [#9084](python-pillow/Pillow#9084) \[[@radarhere](https://github.com/radarhere)] - Ensure dynamic libjpeg libraries are not linked [#9081](python-pillow/Pillow#9081) \[[@freakboy3742](https://github.com/freakboy3742)] - Remove reference to libtiff 3.x [#9072](python-pillow/Pillow#9072) \[[@radarhere](https://github.com/radarhere)] - Restored manylinux2014 wheels [#9059](python-pillow/Pillow#9059) \[[@radarhere](https://github.com/radarhere)] </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.tainton.uk/repos/webexmemebot/pulls/519 Co-authored-by: renovate[bot] <renovate-bot@git.tainton.uk> Co-committed-by: renovate[bot] <renovate-bot@git.tainton.uk>

Improved _accept length check

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hugovk merged commit bde9075 into python-pillow:main Aug 27, 2025
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radarhere deleted the accept branch August 27, 2025 20:06

Improve _accept length check by radarhere · Pull Request #9170 · python-pillow/Pillow · GitHub

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Improve _accept length check - #9170

Improve _accept length check#9170
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Improve _accept length check by radarhere · Pull Request #9170 · python-pillow/Pillow · GitHub

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Improve _accept length check - #9170

Improve _accept length check#9170hugovk merged 1 commit intopython-pillow:mainpython-pillow/Pillow:mainfrom radarhere:acceptradarhere/Pillow:acceptCopy head branch name to clipboard

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Improve _accept length check#9170
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