CVE-2026-15308highCWE-400

CVE-2026-15308: high-severity vulnerability in Python Software Foundation CPython

Incremental HTMLParser feed() allows CPU-exhaustion DoS via repeated unterminated markup declarations

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.7epss 0.6%
The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data.
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
Affected products
Python Software Foundation · CPython
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