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CVE-2026-18503BIT-LIBPYTHON-2026-18503BIT-PYTHON-2026-18503BIT-PYTHON-MIN-2026-18503PSF-2026-35

Super-linear CPU usage for unbounded input to csv.Sniffer.sniff()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

Attacker-controlled CSV samples can trigger super-linear regular-expression work during dialect sniffing and consume significant CPU when applications pass unbounded input to csv.Sniffer.sniff().

Timeline

  1. CVE published
  2. CISA SSVC assessment

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

  3. Record last updated

Affected versions

  • Python Software Foundation CPython

    fixed in 3.10.21; From 3.11.0 · fixed in 3.11.16; From 3.12.0 · fixed in 3.12.14; From 3.13.0 · fixed in 3.13.15; From 3.14.0 · fixed in 3.14.7; From 3.15.0a1 · fixed in 3.15.0rc1; From 3.16.0a1 · fixed in 3.16.0

  • libpythonBitnami

    fixed in 3.10.21; From 3.11.0 · fixed in 3.11.16; From 3.12.0 · fixed in 3.12.14; From 3.13.0 · fixed in 3.13.15; From 3.14.0 · fixed in 3.14.7

  • pythonBitnami

    fixed in 3.10.21; From 3.11.0 · fixed in 3.11.16; From 3.12.0 · fixed in 3.12.14; From 3.13.0 · fixed in 3.13.15; From 3.14.0 · fixed in 3.14.7

  • python-minBitnami

    fixed in 3.10.21; From 3.11.0 · fixed in 3.11.16; From 3.12.0 · fixed in 3.12.14; From 3.13.0 · fixed in 3.13.15; From 3.14.0 · fixed in 3.14.7

References 9

mail.python.org

GitHub · python/cpython