https://seclists.org/oss-sec/2026/q3/110: [oss-security][CVE-2026-15308] Incmental HTMLParser allows CPU-exhaustion DoS via peated unterminated markup declarations

Published Jul 9, 2026
·
Updated

Affected Software

1 affected component
Python CPython<3.15.0
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Frequently Asked Questions

1

What is the severity of CVE-2026-15308?

CVE-2026-15308 is classified as a moderate severity vulnerability that can lead to denial-of-service through CPU exhaustion.

2

How do I fix CVE-2026-15308?

To mitigate CVE-2026-15308, upgrade to Python version 3.15.0 or later.

3

What is the impact of CVE-2026-15308?

CVE-2026-15308 allows attackers to exhaust CPU resources using repeated unterminated markup declarations.

4

Which versions are affected by CVE-2026-15308?

All Python versions before 3.15.0 are affected by CVE-2026-15308.

5

What component of Python is vulnerable in CVE-2026-15308?

CVE-2026-15308 affects the Incremental HTMLParser component of the Python standard library.

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