Vulnerability Description
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().
Related Weaknesses (CWE)
References
- https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee8
- https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c
- https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946
- https://github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c7082a7456002
- https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693
- https://github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47f35d829cf
- https://github.com/python/cpython/issues/98820
- https://github.com/python/cpython/pull/153694
- https://mail.python.org/archives/list/[email protected]/thread/KQ7NBM
FAQ
What is CVE-2026-18503?
CVE-2026-18503 is a documented vulnerability. 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().
How severe is CVE-2026-18503?
CVSS scoring is not yet available for CVE-2026-18503. Check NVD for updates.
Is there a patch for CVE-2026-18503?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.