CVE-2026-9669
bz2.BZ2Decompressor reuse after error can cause a stack buffer overflow
- State
- Published
- Severity
- 8.2 High
- Published
- Jun 8, 2026
- Updated
- Aug 13, 2026
- Reserved
- May 27, 2026
Description
bz2.BZ2Decompressor objects could be reused after a decompression error. If an application caught the resulting OSError and retried with the same decompressor, crafted input could cause the decompressor to resume from an invalid internal state and perform out-of-bounds writes to a stack buffer. This could crash the process when processing untrusted data.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.2 High | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | PSF |
Weaknesses
- CWE-121 Stack-based buffer overflow
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/pull/150600patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/DBJZETMGUIFK7DVUWMOXHD3Z6IX2QPSX/vendor-advisory
- https://github.com/python/cpython/issues/150599issue-tracking
- https://github.com/python/cpython/commit/157a5df8cb5d82b33f918a7489e72ce95ceb12b6patch
- https://github.com/python/cpython/commit/5755d0f083949ff3c5bf3a37e673e24e306b036epatch
- https://github.com/python/cpython/commit/619a12b2e545391dc436b3af79dda22337382a6fpatch
- https://github.com/python/cpython/commit/d3ca26983dfbccdf609f24ff5877dc3118e4702dpatch
- https://github.com/python/cpython/commit/938ec030e90c5e53f1faac6fab1643f14e4f4a79patch
- https://github.com/python/cpython/commit/991e6cf86496718c4ef00b362d640e00cb5c85b2patch
- https://github.com/python/cpython/commit/1ba6135eae75ad8413413caeeedb56ae72320636patch
- http://www.openwall.com/lists/oss-security/2026/06/08/17
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