[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) by encukou · Pull Request #156020 · python/cpython · GitHub

Due to a bug, some Unicode codepoint attributes were considered for characters not yet defined in Unicode 3.2.0 or attributes which changed in later Unicode versions. RFC 3454 (StringPrep) requires using Unicode 3.2.0 strictly.

(cherry picked from commit 7e109d0)

Issue: stringprep and IDNA 2003 incorrectly handles some characters #155292

…RFC 3454 (pythonGH-155293) Due to a bug, some Unicode codepoint attributes were considered for characters not yet defined in Unicode 3.2.0 or attributes which changed in later Unicode versions. RFC 3454 (StringPrep) requires using Unicode 3.2.0 strictly. Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com> Co-authored-by: Petr Viktorin <encukou@gmail.com> (cherry picked from commit 7e109d0)

Note that #144815 wasn't backported to 3.14, so unassigned characters don't have bidi values.

Backport the pending upstream 3.14 backport of the stringprep fix (python/cpython#156020, upstream issue gh-155292): the stringprep module consulted the live Unicode database instead of the Unicode 3.2.0 snapshot mandated by RFC 3454, causing IDNA 2003 mismatches for codepoints added or changed since Unicode 3.2.0. The patch is the squashed, content-identical form of the two PR commits and applies onto the v3.14.7 tag. Signed-off-by: Markus Boehme <markus.boehme@chainguard.dev> Export: c199cf44388ce56624c8472d0abf63865c7e7ccc

… for CVE-2026-17084 (#293385) * fix(python-3.10): backport fix for CVE-2026-17084 The stringprep module consulted the live Unicode database instead of the Unicode 3.2.0 snapshot mandated by RFC 3454, causing IDNA 2003 mismatches for codepoints added or changed since Unicode 3.2.0 (upstream issue gh-155292). Upstream has no 3.10 backport PR yet: the fix is queued behind the still-open 3.14 backport python/cpython#156020, which carries needs-backport labels for 3.10 through 3.13. The patch is derived from that PR, with the unidata_version canary assert in Lib/stringprep.py re-pinned to Unicode 13.0.0 as shipped with Python 3.10, and the "old = False" test class attribute defined, which the new test expects but only 3.13+ provide (introduced by the gh-142681 test refactor that was never backported to security-only branches). The patch content is otherwise identical to the upstream PR. Signed-off-by: Markus Boehme <markus.boehme@chainguard.dev> * fix(python-3.11): backport fix for CVE-2026-17084 The stringprep module consulted the live Unicode database instead of the Unicode 3.2.0 snapshot mandated by RFC 3454, causing IDNA 2003 mismatches for codepoints added or changed since Unicode 3.2.0 (upstream issue gh-155292). Upstream has no 3.11 backport PR yet: the fix is queued behind the still-open 3.14 backport python/cpython#156020, which carries needs-backport labels for 3.10 through 3.13. The patch is derived from that PR, with the unidata_version canary assert in Lib/stringprep.py re-pinned to Unicode 14.0.0 as shipped with Python 3.11, and the "old = False" test class attribute defined, which the new test expects but only 3.13+ provide (introduced by the gh-142681 test refactor that was never backported to security-only branches). The patch content is otherwise identical to the upstream PR. Signed-off-by: Markus Boehme <markus.boehme@chainguard.dev> * fix(python-3.12): backport fix for CVE-2026-17084 The stringprep module consulted the live Unicode database instead of the Unicode 3.2.0 snapshot mandated by RFC 3454, causing IDNA 2003 mismatches for codepoints added or changed since Unicode 3.2.0 (upstream issue gh-155292). Upstream has no 3.12 backport PR yet: the fix is queued behind the still-open 3.14 backport python/cpython#156020, which carries needs-backport labels for 3.10 through 3.13. The patch is derived from that PR, with the unidata_version canary assert in Lib/stringprep.py re-pinned to Unicode 15.0.0 as shipped with Python 3.12, and the "old = False" test class attribute defined, which the new test expects but only 3.13+ provide (introduced by the gh-142681 test refactor that was never backported to security-only branches). The patch content is otherwise identical to the upstream PR. Signed-off-by: Markus Boehme <markus.boehme@chainguard.dev> * fix(python-3.13): backport fix for CVE-2026-17084 The stringprep module consulted the live Unicode database instead of the Unicode 3.2.0 snapshot mandated by RFC 3454, causing IDNA 2003 mismatches for codepoints added or changed since Unicode 3.2.0 (upstream issue gh-155292). Upstream has no 3.13 backport PR yet: the fix is queued behind the still-open 3.14 backport python/cpython#156020, which carries needs-backport labels for 3.10 through 3.13. The patch is derived from that PR, with the unidata_version canary assert in Lib/stringprep.py re-pinned to Unicode 15.1.0 as shipped with Python 3.13. The patch content is otherwise identical to the upstream PR. Signed-off-by: Markus Boehme <markus.boehme@chainguard.dev> --------- Signed-off-by: Markus Boehme <markus.boehme@chainguard.dev> Export: 3ab7270fc25d4029c29fb582a68088006a22dd9e

LGTM, thanks Petr! 🙏

Thanks @encukou for the PR 🌮🎉.. I'm working now to backport this PR to: 3.10, 3.11, 3.12, 3.13.
🐍🍒⛏🤖

Sorry, @encukou, I could not cleanly backport this to 3.12 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 1e54caa096678a38afcabecabb1ff72400dd6bae 3.12

Sorry, @encukou, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 1e54caa096678a38afcabecabb1ff72400dd6bae 3.11

GH-156922 is a backport of this pull request to the 3.13 branch.

Sorry, @encukou, I could not cleanly backport this to 3.10 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 1e54caa096678a38afcabecabb1ff72400dd6bae 3.10

GH-156930 is a backport of this pull request to the 3.12 branch.

GH-156931 is a backport of this pull request to the 3.11 branch.

GH-156932 is a backport of this pull request to the 3.10 branch.

… RFC 3454 (GH-155293) (GH-156020) (#156930) Due to a bug, some Unicode codepoint attributes were considered for characters not yet defined in Unicode 3.2.0 or attributes which changed in later Unicode versions. RFC 3454 (StringPrep) requires using Unicode 3.2.0 strictly. (cherry picked from commit 7e109d0) The cherry-pick needed reworking as GH-144815 wasn't backported to 3.14 and below, so unassigned characters don't have bidi values. (cherry picked from commit 1e54caa) Also, add Unicode_3_2_0_FunctionsTest as in the later versions, to make the new test work. Co-authored-by: Seth Larson seth@python.org Co-authored-by: Stan Ulbrych 89152624+stanfromireland@users.noreply.github.com Co-authored-by: Petr Viktorin encukou@gmail.com

… RFC 3454 (GH-155293) (GH-156020) (GH-156922) Due to a bug, some Unicode codepoint attributes were considered for characters not yet defined in Unicode 3.2.0 or attributes which changed in later Unicode versions. RFC 3454 (StringPrep) requires using Unicode 3.2.0 strictly. (cherry picked from commit 7e109d0) The cherry-pick needed reworking as GH-144815 wasn't backported to 3.14 and below, so unassigned characters don't have bidi values. (cherry picked from commit 1e54caa) Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Seth Larson <seth@python.org> Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com> Co-authored-by: Petr Viktorin <encukou@gmail.com> --------- Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Seth Larson <seth@python.org> Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com>

… RFC 3454 (GH-155293) (GH-156020) (#156932) * [3.10] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) (GH-156020) Due to a bug, some Unicode codepoint attributes were considered for characters not yet defined in Unicode 3.2.0 or attributes which changed in later Unicode versions. RFC 3454 (StringPrep) requires using Unicode 3.2.0 strictly. (cherry picked from commit 7e109d0) The cherry-pick needed reworking as GH-144815 wasn't backported to 3.14 and below, so unassigned characters don't have bidi values. (cherry picked from commit 1e54caa) Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Seth Larson <seth@python.org> Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com> Co-authored-by: Petr Viktorin <encukou@gmail.com> * Add Unicode_3_2_0_FunctionsTest * Regenerate Unicode data --------- Co-authored-by: Seth Larson <seth@python.org> Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com>

… RFC 3454 (GH-155293) (GH-156020) (#156931) * [3.11] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) (GH-156020) Due to a bug, some Unicode codepoint attributes were considered for characters not yet defined in Unicode 3.2.0 or attributes which changed in later Unicode versions. RFC 3454 (StringPrep) requires using Unicode 3.2.0 strictly. (cherry picked from commit 7e109d0) The cherry-pick needed reworking as GH-144815 wasn't backported to 3.14 and below, so unassigned characters don't have bidi values. Co-authored-by: Seth Larson <seth@python.org> Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com> Co-authored-by: Petr Viktorin <encukou@gmail.com> (cherry picked from commit 1e54caa) * Add Unicode_3_2_0_FunctionsTest * Regenerate Unicode data --------- Co-authored-by: Seth Larson <seth@python.org> Co-authored-by: Stan Ulbrych <89152624+stanfromireland@users.noreply.github.com>

sethmlarson and others added 2 commits August 18, 2026 16:46

Re-add test from pythonGH-144815

ff4f6df

encukou requested a review from sethmlarson August 18, 2026 15:13

bedevere-app Bot mentioned this pull request Aug 18, 2026

stringprep and IDNA 2003 incorrectly handles some characters #155292

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bedevere-app Bot added the awaiting core review label Aug 18, 2026

encukou changed the title gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) [3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) Aug 18, 2026

bedevere-app Bot added topic-unicode type-security A security issue labels Aug 18, 2026

bedevere-app Bot mentioned this pull request Aug 18, 2026

gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 #155293

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encukou requested a review from StanFromIreland August 19, 2026 08:35

encukou added needs backport to 3.10 needs backport to 3.11 only security fixes needs backport to 3.12 only security fixes needs backport to 3.13 only security fixes labels Sep 1, 2026

sethmlarson approved these changes Sep 3, 2026

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bedevere-app Bot added awaiting merge and removed awaiting core review labels Sep 3, 2026

encukou merged commit 1e54caa into python:3.14 Sep 4, 2026
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encukou deleted the backport-7e109d0-3.14 branch September 4, 2026 09:29

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[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) by encukou · Pull Request #156020 · python/cpython · GitHub

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[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) - #156020

[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293)#156020
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[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293) by encukou · Pull Request #156020 · python/cpython · GitHub

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[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293)#156020encukou merged 2 commits intopython:3.14python/cpython:3.14from encukou:backport-7e109d0-3.14encukou/cpython:backport-7e109d0-3.14Copy head branch name to clipboard

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[3.14] gh-155292: Don't consider Unicode codepoint attributes outside RFC 3454 (GH-155293)#156020
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