Detections
Analytics

CVE-2026-18503

low

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().

References

https://mail.python.org/archives/list/[email protected]/thread/KQ7NBMCPAZJHRROQXJQE4GMXGLD5KHBS/

https://github.com/python/cpython/pull/153694

https://github.com/python/cpython/issues/98820

https://github.com/python/cpython/commit/b30c7fa9edd921a118f286e9f90f560777fa693b

https://github.com/python/cpython/commit/89f29c760c02774b099ddd6863268eb13fa3946a

https://github.com/python/cpython/commit/476fb09cdb0d73e645849d98c610e7e5697ce7c9

https://github.com/python/cpython/commit/063d4555c94ef412c731527dbf30193327f2ee82

Details

Source: Mitre, NVD

Published: 2026-08-10

Updated: 2026-08-10

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

Severity: Medium

CVSS v3

Base Score: 9.1

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 2.4

Vector: 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

Severity: Low