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().
References10
- github.com/python/cpython/commit/063d4555c94ef412c731527dbf3019…
- github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7…
- github.com/python/cpython/commit/89f29c760c02774b099ddd6863268e…
- github.com/python/cpython/commit/b09a67a20c464f8288c9f9a6b9c708…
- github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f56…
- github.com/python/cpython/commit/fd78b565d7c326f96ae903ab945b47…
- github.com/python/cpython/issues/98820
- github.com/python/cpython/pull/153694
- mail.python.org/archives/list/[email protected]/thre…
- cert-portal.siemens.com/productcert/html/ssa-457936.html
Metrics
- CVSS 4.0
-
2.4
LOW
Score source: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 2 · as of 12 November 2026
- CWE
- CWE-1176
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.