CVE-2026-42772
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.
Leer descripción completaMostrar menos
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
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Puntuación base: 5.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.33%
- Percentil entre todas las CVEs puntuadas: 24
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access85 % - Impacto principal
T1499.004Application or System Exploitationimpact90 %
Vulnerabilidad de complejidad algorítmica en QUIC de OpenSSL remota (AV:N, sin autenticación previa al handshake). Causa DoS por CPU exhaustion mediante frames STREAM manipulados. T1499.004 (application exhaustion) es el impacto directo.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-407
Referencias
- https://github.com/openssl/openssl/commit/32d0ed8afe1b8c3e7ece725b44663da3d7087a09
- https://github.com/openssl/openssl/commit/ca8402e273af4de5b3f04fa61a0f0c02ce3ae20e
- https://github.com/openssl/openssl/commit/eb2becc0a4baea7f3050a247834d0e5c2ebe1773
- https://github.com/openssl/openssl/commit/f42ae513bbda513b3c121d54834040ee4a0eae1a
- https://openssl-library.org/news/secadv/20260929.txt
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-42772",
"cveTags": [],
"metrics": {
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{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"role": "CISA Coordinator",
"options": [
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"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
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],
"version": "2.0.3",
"timestamp": "2026-09-30T19:35:54.157005Z"
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"cvssMetricV31": [
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"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "LOW",
"privilegesRequired": "NONE",
"confidentialityImpact": "NONE"
},
"impactScore": 1.4,
"exploitabilityScore": 3.9
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"affected": [
{
"source": "openssl-security@openssl.org",
"affectedData": [
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"lessThan": "4.0.3",
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"published": "2026-09-29T16:17:07.640",
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"description": [
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"value": "Issue summary: The QUIC stream reassembly algorithm performance deteriorates\nprogressively as packets are arriving out of order. The worst case has\na quadratic complexity proportional to the number of stream frames kept in\nthe buffer for the received stream data.\n\nImpact summary: A remote QUIC peer that completes the handshake can create\na connection-scoped CPU pressure and potentially a Denial of Service using\ncompliant STREAM frames inside the advertised receive window, with low\nattacker bandwidth.\n\nCWE: CWE-407: Inefficient Algorithmic Complexity\n\nDescription: OpenSSL manages received QUIC stream fragments using a\ndoubly-linked list. While it optimizes for append operations (at the end of\nthe list), it falls back to a head-to-tail linear search for any fragment\nthat does not immediately follow the current `tail`.\n\nBy manipulating the sequence of offsets, an attacker can force the server\nto perform O(n^2) operations, consuming excessive CPU time for the\nQUIC process.\n\nFIPS impact: no\nThe FIPS module is not affected as the QUIC implementation is outside of\nthe OpenSSL FIPS module boundary."
}
],
"lastModified": "2026-09-30T21:17:10.803",
"sourceIdentifier": "openssl-security@openssl.org"
}