CVE-2026-9669

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.

• CWE-121

• https://github.com/python/cpython/commit/157a5df8cb5d82b33f918a7489e72ce95ceb12b6
• https://github.com/python/cpython/commit/5755d0f083949ff3c5bf3a37e673e24e306b036e
• https://github.com/python/cpython/commit/619a12b2e545391dc436b3af79dda22337382a6f
• https://github.com/python/cpython/commit/d3ca26983dfbccdf609f24ff5877dc3118e4702d
• https://github.com/python/cpython/issues/150599
• https://github.com/python/cpython/pull/150600
• https://mail.python.org/archives/list/security-announce@python.org/thread/DBJZETMGUIFK7DVUWMOXHD3Z6IX2QPSX/
• http://www.openwall.com/lists/oss-security/2026/06/08/17

Published

Jun 8, 2026

Last Modified

Jun 23, 2026

Status

Awaiting Analysis