Is h11 affected by CVE-2025-43859?

PyPI h11 is affected in <0.16.0.

Is CVE-2025-43859 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.5%.

critical

CVE-2025-43859

Q: Is CVE-2025-43859 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.5%.

PyPI · h11

Summary

h11 accepts some malformed Chunked-Encoding bodies

Severity: critical
EPSS: 0.5% (p40)
Also known as: GHSA-vqfr-h8mv-ghfj
Published: 2025-04-24

References

https://github.com/python-hyper/h11/security/advisories/GHSA-vqfr-h8mv-ghfj
https://nvd.nist.gov/vuln/detail/CVE-2025-43859
https://github.com/python-hyper/h11/commit/114803a29ce50116dc47951c690ad4892b1a36ed

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.