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CVE PROGRAM SOURCE RECORD5.3 Medium

CVE-2026-42772

Potential CPU DoS via O(n^2) Fragment Reassembly in QUIC

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Status
Published
Published
Updated
Assigning organization
openssl

Description

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

OpenSSL OpenSSL

Default version status: unaffected

  • 4.0.0 to < 4.0.3affected
  • 3.6.0 to < 3.6.5affected
  • 3.5.0 to < 3.5.9affected
  • 3.4.0 to < 3.4.8affected

References