CVE-2026-42772

NameCVE-2026-42772
DescriptionIssue summary: The QUIC stream reassembly algorithm performance deteriorates progressively as packets are arriving out of order. The worst case has a quadratic complexity proportional to the number of stream frames kept in the buffer for the received stream data. Impact summary: A remote QUIC peer that completes the handshake can create a connection-scoped CPU pressure and potentially a Denial of Service using compliant STREAM frames inside the advertised receive window, with low attacker bandwidth. CWE: CWE-407: Inefficient Algorithmic Complexity Description: OpenSSL manages received QUIC stream fragments using a doubly-linked list. While it optimizes for append operations (at the end of the list), it falls back to a head-to-tail linear search for any fragment that does not immediately follow the current `tail`. By manipulating the sequence of offsets, an attacker can force the server to perform O(n^2) operations, consuming excessive CPU time for the QUIC process. FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6531-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)bookworm3.0.20-1~deb12u2fixed
bookworm (security)3.0.22-1~deb12u1fixed
trixie3.5.7-1~deb13u2vulnerable
trixie (security)3.5.7-1~deb13u3fixed
forky3.6.4-1vulnerable
sid3.6.5-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
opensslsourcebookworm(not affected)
opensslsourcetrixie3.5.7-1~deb13u3DSA-6531-1
opensslsource(unstable)3.6.5-1

Notes

[bookworm] - openssl <not-affected> (Vulnerable code not present)
https://openssl-library.org/news/secadv/20260929.txt

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