PYSEC-2026-4053 hpack: Unbounded variable integer decoding can cause run-away computation on malformed input

Impact Users of the python-hyper/hpack library, most commonly used as downstream dependency of the python-hyper/h2 library an HTTP/2 client and server implementation. Unbounded variable integer decoding can cause run-away computation on malformed input leading to On^2 runtime, effectively blockin...

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

Impact Users of the python-hyper/hpack library, most commonly used as downstream dependency of the python-hyper/h2 library an HTTP/2 client and server implementation. Unbounded variable integer decoding can cause run-away computation on malformed input leading to On^2 runtime, effectively blockin...

DEBIAN-CVE-2026-59980

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 On^2 runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpa...

CVE-2026-59980

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 On^2 runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpa...

CVE-2026-59980: Uncontrolled Resource Consumption

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 On^2 runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpa...

PT-2026-89705

An issue was found in the python-hyper/hpack library, most commonly used as a downstream dependency of the python-hyper/h2 library an HTTP/2 client and server implementation. Unbounded variable integer decoding can cause run-away computation on malformed input leading to On^2 runtime, effectively...

PT-2026-80780

Name of the Vulnerable Software and Affected Versions hpack versions prior to 4.2.0 Description Unbounded variable integer decoding can cause run-away computation when processing malformed input, resulting in On^2 runtime. This can effectively block further processing if the unsanitized input is...