[3.11] gh-90949: add Expat API to prevent XML deadly allocations (CVE-2025-59375) (GH-139234)#139529
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…2025-59375) (python#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)
…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)). |
Contributor
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
ContributorAuthor
hartwork commented Nov 8, 2025
@pablogsal do you have a minute for this? |
ContributorAuthor
hartwork commented Nov 22, 2025
@pablogsal do you have a minute for this? 🙏 |
pablogsal approved these changes Nov 25, 2025
pablogsal merged commit 9bbb68a into python:3.11 24 checks passed
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pablogsal commented Nov 25, 2025
Thanks a lot for the backport and thanks for the patience :) |
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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--139529.org.readthedocs.build/