[3.12] gh-90949: add Expat API to prevent XML deadly allocations (CVE-2025-59375) (GH-139234)#139527
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CVE-2025-59375) (pythonGH-139234) Expose the XML Expat 2.7.2 mitigation APIs to disallow use of disproportional amounts of dynamic memory from within an Expat parser (see CVE-2025-59375 for instance). The exposed APIs are available on Expat parsers, that is, parsers created by `xml.parsers.expat.ParserCreate()`, as: - `parser.SetAllocTrackerActivationThreshold(threshold)`, and - `parser.SetAllocTrackerMaximumAmplification(max_factor)`. (cherry picked from commit f04bea4) Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
…on API (python#139366) Fix some typos left in f04bea4, and simplify some internal functions to ease maintenance of future mitigation APIs. (cherry picked from commit 68a1778)
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picnixz commented Oct 7, 2025
To have a good synchronization, we'll also delay 3.10 to 3.13 backports for their next release cycle (see #139359 (comment)). |
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ambv commented Oct 8, 2025
I set DO-NOT-MERGE to avoid confusion. Unset that when you think we should be releasing this. |
picnixz approved these changes Nov 8, 2025
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The 22 additional lines are in the clinic file so all good.
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hartwork commented Nov 22, 2025
@Yhg1s do you have a minute for this? 🙏 |
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hartwork commented Dec 17, 2025
@Yhg1s do you have a minute? 🙏 |
Yhg1s merged commit 0e4cd89 into python:3.12 30 checks passed
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hartwork commented Dec 17, 2025
Thanks! 🙏 |
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Expose the XML Expat 2.7.2 mitigation APIs to disallow use of disproportional amounts of dynamic memory from within an Expat parser (see CVE-2025-59375 for instance).
The exposed APIs are available on Expat parsers, that is, parsers created by
xml.parsers.expat.ParserCreate(), as:parser.SetAllocTrackerActivationThreshold(threshold), andparser.SetAllocTrackerMaximumAmplification(max_factor).(cherry picked from commit f04bea4)
CC @picnixz
📚 Documentation preview 📚: https://cpython-previews--139527.org.readthedocs.build/