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CVE-2026-59980

hpack: Unbounded variable integer decoding can cause run-away computation on malformed input PUBLISHED

Description (CNA)

hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use.

Affected (CNA)

Vendor / productVersions
python-hyper / hpackaffected < 4.2.0

CWE

CWE-400

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.