CPython bz2 Reuse After Error Causing OOB Stack Write 3.15
CVE-2026-9669 Published on June 8, 2026
bz2.BZ2Decompressor reuse after error can cause a stack buffer overflow
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.
Weakness Type
What is a Stack Overflow Vulnerability?
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CVE-2026-9669 has been classified to as a Stack Overflow vulnerability or weakness.
Products Associated with CVE-2026-9669
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Affected Versions
Python Software Foundation CPython:- Before 3.13.14 is affected.
- Version 3.14.0 and below 3.14.6 is affected.
- Version 3.15.0a1 and below 3.15.0b3 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.