CVE-2026-80550
In the Linux kernel, the following vulnerability has been resolved:
s390/vfio_ccw: Fix out of bounds check on CCW array
The routine ccwchain_calc_length() counts the number of channel command words (CCWs) that are chained together in a single channel program, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs.
The loop itself is "do..while (count < 257)", and while the logic in is_cpa_within_range() correctly adjusts between the 0-index array of CCWs and the count of CCWs starting at 1, this means it would look at a possible 257th CCW before ending the loop and (correctly) returning an error.
Leer descripción completaMostrar menos
Fix this by restructuring the loop to break as soon as 256 CCWs (thus indexes 0-255) are examined, without looking at memory outside the range.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L
- Puntuación base: 7.9
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.18%
- Percentil entre todas las CVEs puntuadas: 7
- 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
T1499.004Application or System Exploitationimpact75 %
Acceso local sin interacción (AV:L, UI:N, PR:N) en kernel Linux; el desbordamiento de búfer en ccwchain_calc_length() permite lectura de memoria fuera de límites causando DoS local.
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/0282fb1c4b638eecfe2cc558092c460911d8f7e2
- https://git.kernel.org/stable/c/499a8a66b1598bfab97182aed15e0f1646074a3d
- https://git.kernel.org/stable/c/4c2e1d359d7a2b82cdf3254e4e480af9417f99fb
- https://git.kernel.org/stable/c/907adc667d902fafbdb2d740d57b55bd025dc4cd
- https://git.kernel.org/stable/c/a005b7f1a491ffda61bff0fd0f6548f8986fb977
- https://git.kernel.org/stable/c/af3f80ca4c8b17f20f9e588def076288fdb49e65
- https://git.kernel.org/stable/c/d5d096cd9369e986d4e5153baa86b8b35c283e09
- https://git.kernel.org/stable/c/f20be33d093ce7630c17ff7ed93caf7eaf8ac1a3
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-80550",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 7.9,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:L",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "LOW",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 4.7,
"exploitabilityScore": 2.5
}
]
},
"affected": [
{
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"affectedData": [
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"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
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{
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],
"programFiles": [
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],
"defaultStatus": "unaffected"
},
{
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"versions": [
{
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},
{
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{
"status": "unaffected",
"version": "5.10.266",
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{
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},
{
"status": "unaffected",
"version": "6.1.184",
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},
{
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "6.18.46",
"versionType": "semver",
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},
{
"status": "unaffected",
"version": "7.1.10",
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},
{
"status": "unaffected",
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"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
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],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-26T15:17:09.477",
"references": [
{
"url": "https://git.kernel.org/stable/c/0282fb1c4b638eecfe2cc558092c460911d8f7e2",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
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{
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{
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{
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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\ns390/vfio_ccw: Fix out of bounds check on CCW array\n\nThe routine ccwchain_calc_length() counts the number of channel\ncommand words (CCWs) that are chained together in a single channel\nprogram, and rejects anything larger than CCWCHAIN_LEN_MAX (256) CCWs.\n\nThe loop itself is \"do..while (count < 257)\", and while the logic in\nis_cpa_within_range() correctly adjusts between the 0-index array of\nCCWs and the count of CCWs starting at 1, this means it would look\nat a possible 257th CCW before ending the loop and (correctly)\nreturning an error.\n\nFix this by restructuring the loop to break as soon as 256 CCWs\n(thus indexes 0-255) are examined, without looking at memory\noutside the range."
}
],
"lastModified": "2026-08-27T06:17:37.617",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}