CVE-2026-9669
High
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.
SeverityHigh
CVSS8.2
Exploit probability—
ProductCPython
PublishedJun 8, 2026
First seenJun 8, 2026
Weakness typeCWE-121CWE-121
How to fix
Update
- Python Software Foundation CPython3.10.21, 3.11.16, 3.12.14, 3.13.14, 3.14.6, 3.15.0b3 or later
Patches
- github.com/python/cpython/pull/150600
- github.com/python/cpython/commit/157a5df8cb5d82b33f918a7489e72ce95ceb12b6
- github.com/python/cpython/commit/5755d0f083949ff3c5bf3a37e673e24e306b036e
- github.com/python/cpython/commit/619a12b2e545391dc436b3af79dda22337382a6f
- github.com/python/cpython/commit/d3ca26983dfbccdf609f24ff5877dc3118e4702d
- github.com/python/cpython/commit/938ec030e90c5e53f1faac6fab1643f14e4f4a79
- github.com/python/cpython/commit/991e6cf86496718c4ef00b362d640e00cb5c85b2
- github.com/python/cpython/commit/1ba6135eae75ad8413413caeeedb56ae72320636
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Python Software Foundation CPython | v < 3.10.21, 3.11.0 ≤ v < 3.11.16, 3.12.0 ≤ v < 3.12.14, 3.13.0 ≤ v < 3.13.14, 3.14.0 ≤ v < 3.14.6, 3.15.0a1 ≤ v < 3.15.0b3 | 3.10.21, 3.11.16, 3.12.14, 3.13.14, 3.14.6, 3.15.0b3 |
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