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4.3 Medium

CVE-2025-6069 The html.parser.HTMLParser class had worse-case quadratic complexity when processing certain crafted malformed inputs…

Description

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

Affected products and versions

Product Affected versions Fixed in
CPython 3.14 3.14.0a1 → < 3.14.0b3 3.14.0b3
CPython 3.13 3.13.0 → < 3.13.6 3.13.6
CPython 3.12 3.12.0 → < 3.12.12 3.12.12
CPython 3.11 3.11.0 → < 3.11.14 3.11.14
CPython 3.10 3.10.0 → < 3.10.19 3.10.19
CPython 3.9 earliest → < 3.9.24 3.9.24

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