CVE-2026-15308

high

Description

The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.

References

https://mail.python.org/archives/list/[email protected]/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/

https://github.com/python/cpython/pull/153031

https://github.com/python/cpython/issues/153030

https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd

https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606

https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced

https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9

http://www.openwall.com/lists/oss-security/2026/07/09/4

Details

Source: Mitre, NVD

Published: 2026-07-09

Updated: 2026-07-09

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: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Severity: High

CVSS v4

Base Score: 8.7

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N