cve.bz

CVE-2026-42772

5.3 mediumEPSS 0.5%

Issue 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.

CVSS 3.1
5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS
0.5% chance of exploitation in the next 30 days; higher than 41% of CVEs (scores of 2026-10-25)
CWE
CWE-407
Published
Modified
Record from
the NVD, synced

Affected

References

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