The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.
Fix
Patch, vendor advisory and mitigation references on NVD 9
- https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9 Patch
- https://github.com/python/cpython/commit/1e7956f1a722df9aabc509c30f8fbdc3a2b4fdc7 Patch
- https://github.com/python/cpython/commit/785df8f743800661961528970f8598edcd291c14 Patch
- https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced Patch
- https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606 Patch
- https://github.com/python/cpython/commit/c2390b9376e35a701ed3acc597b8fc87546c9b00 Patch
- https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd Patch
- https://github.com/python/cpython/issues/153030 Patch
- https://github.com/python/cpython/pull/153031 Issue Tracking, Patch
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 8.7 · pythonNVD modified 2026-10-25 17:10
Affected (CPE criteria) 12
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha1:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha2:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha3:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha4:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha5:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha6:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha7:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:alpha8:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:beta1:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:beta2:*:*:*:*:*:*cpe:2.3:a:python:python:3.15.0:beta3:*:*:*:*:*:*
References 11
- https://github.com/python/cpython/commit/07efb08123ba9367a7107325adb9d5626dca1ca9 Patch
- https://github.com/python/cpython/commit/1e7956f1a722df9aabc509c30f8fbdc3a2b4fdc7 Patch
- https://github.com/python/cpython/commit/785df8f743800661961528970f8598edcd291c14 Patch
- https://github.com/python/cpython/commit/7933f4bf7131aa4140750f9404f5de0aa2969ced Patch
- https://github.com/python/cpython/commit/bcf98ddbc40ec9b3ee87da0124a5660b19b7e606 Patch
- https://github.com/python/cpython/commit/c2390b9376e35a701ed3acc597b8fc87546c9b00 Patch
- https://github.com/python/cpython/commit/e9f92ac0b298292e7ff998e52cb8ccacfb27a0bd Patch
- https://github.com/python/cpython/issues/153030 Patch
- https://github.com/python/cpython/pull/153031 Issue Tracking, Patch
- https://mail.python.org/archives/list/[email protected]/thread/F6453LWKSHKCTWFLCOURWPLETNUIW2Z5/ Mailing List
- http://www.openwall.com/lists/oss-security/2026/07/09/4 Third Party Advisory