CVE-2016-6581

NameCVE-2016-6581
DescriptionA HTTP/2 implementation built using any version of the Python HPACK library between v1.0.0 and v2.2.0 could be targeted for a denial of service attack, specifically a so-called "HPACK Bomb" attack. This attack occurs when an attacker inserts a header field that is exactly the size of the HPACK dynamic header table into the dynamic header table. The attacker can then send a header block that is simply repeated requests to expand that field in the dynamic table. This can lead to a gigantic compression ratio of 4,096 or better, meaning that 16kB of data can decompress to 64MB of data on the target machine.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs833467

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
python-hpack (PTS)buster3.0.0-3fixed
trixie, sid, bookworm, bullseye4.0.0-2fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
python-hpacksource(unstable)2.3.0-1833467

Notes

https://github.com/python-hyper/hpack/pull/56

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