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CVE-2026-96749PYSEC-2026-4296GHSA-V4X9-3549-CRWV

Heap out-of-bounds write via signed size overflow in BSON document encoding

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.18.2
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

An integer overflow in the BSON document encoding component of the MongoDB Python Driver's bundled native extension may occur when a single document is built from an unusually large amount of caller-supplied data. Size arithmetic is performed in a signed 32-bit type, and the guard meant to catch the overflow is written in a form whose behavior is not defined by the C language standard. A party with no privileges who can place a very large value into data that an application encodes may, depending on how the native extension was built, cause a write outside the bounds of an allocated buffer inside the application's own process.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • MongoDB Python Driver

    From 1.9.0 · fixed in 4.18.2

  • pymongoPyPI

    fixed in 4.18.2

References 3

GitHub · mongodb/mongo-python-driver