5.3

CVE-2026-42772

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

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.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
OpenSSL ≫ OpenSSL Version >= 3.4.0 < 3.4.8
OpenSSL ≫ OpenSSL Version >= 3.5.0 < 3.5.9
OpenSSL ≫ OpenSSL Version >= 3.6.0 < 3.6.5
OpenSSL ≫ OpenSSL Version >= 4.0.0 < 4.0.3
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.33% 0.237
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
CISA-ADP 5.3 3.9 1.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE-407 Inefficient Algorithmic Complexity

An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

https://openssl-library.org/news/secadv/20260929.txt
Vendor Advisory
https://github.com/openssl/openssl/commit/32d0ed8afe1b8c3e7ece725b44663da3d7087a09
Patch
https://github.com/openssl/openssl/commit/ca8402e273af4de5b3f04fa61a0f0c02ce3ae20e
Patch
https://github.com/openssl/openssl/commit/eb2becc0a4baea7f3050a247834d0e5c2ebe1773
Patch
https://github.com/openssl/openssl/commit/f42ae513bbda513b3c121d54834040ee4a0eae1a
Patch