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Low 2.4Published Aug 10, 2026
CVE-2026-18503Super-linear CPU usage for unbounded input to csv.Sniffer.sniff()
Updated under an hour ago ()
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It affects Python Software Foundation CPython. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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().
- CVSS
- 2.4 LOW (v4.0, CNA)CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-1176
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- PSF
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 14, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Python Software Foundation CPython python_software_foundation:cpython (from the name) | before 3.10.21; from 3.11.0 before 3.11.16; from 3.12.0 before 3.12.14; from 3.13.0 before 3.13.15; from 3.14.0 before 3.14.7; from 3.15.0a1 before 3.15.0rc1; from 3.16.0a1 before 3.16.0 | CNA record |
References
- https://mail.python.org/archives/list/security-announce@python.org/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS/vendor-advisory
- https://github.com/python/cpython/pull/153694patch
- https://github.com/python/cpython/issues/98820issue-tracking
- https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82patch
- https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9patch
- https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946apatch
- https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693bpatch
- https://github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c7082a74560024patch
- https://github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47f35d829cf4patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.