Description
The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Python Software Foundation CPython
Default version status: unaffected
0 to < 3.10.21affected3.11.0 to < 3.11.16affected3.12.0 to < 3.12.14affected3.13.0 to < 3.13.15affected3.14.0 to < 3.14.7affected3.15.0a1 to < 3.15.0b4affected
References
- https://mail.python.org/archives/list/security-announce@python.org/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/ ↗
- https://github.com/python/cpython/pull/153031 ↗
- https://github.com/python/cpython/issues/153030 ↗
- https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9 ↗
- https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced ↗
- https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606 ↗
- https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd ↗
- https://github.com/python/cpython/commit/785df8f743800661961528970f8598edcd291c14 ↗
- https://github.com/python/cpython/commit/1e7956f1a722df9aabc509c30f8fbdc3a2b4fdc7 ↗
- https://github.com/python/cpython/commit/c2390b9376e35a701ed3acc597b8fc87546c9b00 ↗
- http://www.openwall.com/lists/oss-security/2026/07/09/4 ↗