CVE-2026-74579
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_payload: fix mask build for partial field offload
nft_payload_offload_mask() builds the offload match mask for a payload expression that covers only part of a header field. For a partial IPv6 address match (field_len = 16, priv_len = 1) that shift is 1 << 120, which is undefined on the 32-bit int operand. It also trims only one word, so the remaining words stay 0xffffffff (and when priv_len is a multiple of 4 the trim is skipped entirely), leaving the mask covering more bytes than the rule matches.
The match is byte-granular and struct nft_data is zero-initialised, so the correct mask is simply the first priv_len bytes set to 0xff.
Leer descripción completaMostrar menos
Set those bytes directly and drop the word/shift trimming; this removes the undefined shift and no longer over-masks the trailing bytes.
Detalles técnicos trazas, registros y código del informe original
UBSAN: shift-out-of-bounds in net/netfilter/nft_payload.c:278:20 shift exponent 120 is too large for 32-bit type 'int' ...
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- Puntuación base: 7.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.12%
- Percentil entre todas las CVEs puntuadas: 2
- Fecha de la puntuación: 6/10/2026
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
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1565.002Transmitted Data Manipulationimpact70 % - Impacto secundario
T1499.004Application or System Exploitationimpact65 %
Escalada de privilegios local (PR:L, AV:L) sin interacción. Corrupción de máscara en netfilter causa manipulación de reglas de red (I:H) e impacto de disponibilidad (A:H).
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.
Referencias
- https://git.kernel.org/stable/c/16b553c46e347bc9de9946c4960654d5884a86de
- https://git.kernel.org/stable/c/363c3a84a946d53e5e121c9f47c7c2b7d228c46b
- https://git.kernel.org/stable/c/39e88f28fb32bf02bd4b525c24c842c9cff5663d
- https://git.kernel.org/stable/c/3ee7b3f813b11f28cd6efdf7f24d64b5a7fd4dc7
- https://git.kernel.org/stable/c/630295d5bba1d0e0f494cc459452eb0a0058c545
- https://git.kernel.org/stable/c/8720df4504e0ed1781a702f65251bd47b3534d5e
- https://git.kernel.org/stable/c/a375d8ace807767f29f276b681b6324c74929b1d
- https://git.kernel.org/stable/c/b19b5d2e042c294e2cc1c908dc598f9d64015396
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-74579",
"cveTags": [],
"metrics": {
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{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.1,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "NONE"
},
"impactScore": 5.2,
"exploitabilityScore": 1.8
}
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},
{
"status": "unaffected",
"version": "6.1.183",
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{
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"version": "6.6.151",
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"published": "2026-08-17T06:19:56.417",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_payload: fix mask build for partial field offload\n\nnft_payload_offload_mask() builds the offload match mask for a payload\nexpression that covers only part of a header field. For a partial IPv6\naddress match (field_len = 16, priv_len = 1) that shift is 1 << 120, which\nis undefined on the 32-bit int operand. It also trims only one word, so\nthe remaining words stay 0xffffffff (and when priv_len is a multiple of 4\nthe trim is skipped entirely), leaving the mask covering more bytes than\nthe rule matches.\n\n UBSAN: shift-out-of-bounds in net/netfilter/nft_payload.c:278:20\n shift exponent 120 is too large for 32-bit type 'int'\n ...\n\nThe match is byte-granular and struct nft_data is zero-initialised, so the\ncorrect mask is simply the first priv_len bytes set to 0xff. Set those\nbytes directly and drop the word/shift trimming; this removes the undefined\nshift and no longer over-masks the trailing bytes."
}
],
"lastModified": "2026-08-25T06:18:30.677",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}