CVE-2025-6069

MEDIUM

html.parser - DoS

Title source: llm

Description

The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs potentially leading to amplified denial-of-service.

References (10)

[Issue Tracking] https://github.com/python/cpython/issues/135462

[Various Sources] https://mail.python.org/archives/list/[email protected]/thread/K5PIYLR6EP3WR7ZOKKYQUWEDNQVUXOYM/

[Patch] https://github.com/python/cpython/commit/4455cbabf991e202185a25a631af206f60bbc949

View Patch ZIP pw:eip

[Patch] https://github.com/python/cpython/commit/6eb6c5dbfb528bd07d77b60fd71fd05d81d45c41

[Patch] https://github.com/python/cpython/commit/d851f8e258c7328814943e923a7df81bca15df4b

[Patch] https://github.com/python/cpython/commit/8d1b3dfa09135affbbf27fb8babcf3c11415df49

[Patch] https://github.com/python/cpython/commit/ab0893fd5c579d9cea30841680e6d35fc478afb5

[Patch] https://github.com/python/cpython/commit/f3c6f882cddc8dc30320d2e73edf019e201394fc

[Patch] https://github.com/python/cpython/commit/fdc9d214c01cb4588f540cfa03726bbf2a33fc15

[Issue Tracking] https://github.com/python/cpython/pull/135464

Scores

CVSS v3 4.3

EPSS 0.0086

EPSS Percentile 75.2%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact partial

Details

CWE

CWE-1333

Status published

Products (7)

Python Software Foundation/CPython < 3.10.19

Python Software Foundation/CPython < 3.9.24

Python Software Foundation/CPython 3.10.0 - 3.10.19

Python Software Foundation/CPython 3.11.0 - 3.11.14

Python Software Foundation/CPython 3.12.0 - 3.12.12

Python Software Foundation/CPython 3.13.0 - 3.13.6

Python Software Foundation/CPython 3.14.0a1 - 3.14.0b3

Published Jun 17, 2025

Tracked Since Feb 18, 2026