CVE-2026-18503
CVE-2026-18503 is a low-severity vulnerability with a CVSS 4.0 base score of 2.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1176.
Key facts
- Severity: Low (CVSS 4.0 base score 2.4)
- EPSS exploit prediction: 0% (2nd percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-1176
- Published:
- Last modified:
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().
Frequently asked questions
- What is CVE-2026-18503?
- 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?
- CVE-2026-18503 has a CVSS 4.0 base score of 2.4, rated low severity.
- Is CVE-2026-18503 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-18503?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2026-18503 published?
- CVE-2026-18503 was published on 2026-08-10 and last updated on 2026-08-18.
References
- https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82
- https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9
- https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946a
- https://github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c7082a74560024
- https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693b
- https://github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47f35d829cf4
- https://github.com/python/cpython/issues/98820
- https://github.com/python/cpython/pull/153694
- https://mail.python.org/archives/list/[email protected]/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS/
Other CWE-1176 vulnerabilities
- CVE-2025-46153 — Medium (CVSS 5.3): PyTorch before 3.7.0 has a bernoulli_p decompose function in decompositions.py even though it lacks full consistency…