CVE-2026-89918
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Correctly handle end of VA space TLBI invalidation
Our TLB invalidation by VA code is based on comparing two ranges, one defined by the TLB, and one defined by the TLBI instruction.
Each range is defined by a start and a size. However, the way the comparison is done doesn't account for address rollover, as it compares an address with (base + size). This works nicely until this expression represent the last page/block in the TTBR1 VA space, as the result is a big fat 0. And a failed TLB invalidation.
Rewrite the comparison in a way that is immune to the address rollover (making the end address inclusive instead of exclusive), and move this into a common helper that is used by both VA and IPA invalidations, as suggested by Hyunwoo Kim (although the IPA version didn't suffer from this particular problem, obviously).
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Puntuación base: 9.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.19%
- Percentil entre todas las CVEs puntuadas: 8
- 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
T1068Exploitation for Privilege Escalationprivilege escalation85 %
Vulnerabilidad local (AV:L, PR:N) en kernel KVM arm64 que permite eludir validaciones de TLB y alcanzar máquina virtual, causando escalada de privilegios. El fallo de rollover en direcciones permite acceso no autorizado a memoria de máquinas virtuales, generando denegación de servicio.
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
JSON original (NVD)
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{
"id": "CVE-2026-89918",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 9.3,
"attackVector": "LOCAL",
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 6,
"exploitabilityScore": 2.5
}
]
},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4ffa72ad8f37e73bbb6c0baa88557bcb4fd39929",
"lessThan": "ce447651a52ec077694172af10c4fffb11f56c43",
"versionType": "git"
},
{
"status": "affected",
"version": "4ffa72ad8f37e73bbb6c0baa88557bcb4fd39929",
"lessThan": "c624731ca6fe59ad8909ce4108301aa7560a91d6",
"versionType": "git"
},
{
"status": "affected",
"version": "4ffa72ad8f37e73bbb6c0baa88557bcb4fd39929",
"lessThan": "34af2c3e31f91a739dc175459fdbd99ed952b457",
"versionType": "git"
}
],
"programFiles": [
"arch/arm64/kvm/nested.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.16"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.16",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/arm64/kvm/nested.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-16T11:17:00.867",
"references": [
{
"url": "https://git.kernel.org/stable/c/34af2c3e31f91a739dc175459fdbd99ed952b457",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c624731ca6fe59ad8909ce4108301aa7560a91d6",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ce447651a52ec077694172af10c4fffb11f56c43",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Correctly handle end of VA space TLBI invalidation\n\nOur TLB invalidation by VA code is based on comparing two ranges,\none defined by the TLB, and one defined by the TLBI instruction.\n\nEach range is defined by a start and a size. However, the way the\ncomparison is done doesn't account for address rollover, as it\ncompares an address with (base + size). This works nicely until\nthis expression represent the last page/block in the TTBR1 VA space,\nas the result is a big fat 0. And a failed TLB invalidation.\n\nRewrite the comparison in a way that is immune to the address\nrollover (making the end address inclusive instead of exclusive),\nand move this into a common helper that is used by both VA and IPA\ninvalidations, as suggested by Hyunwoo Kim (although the IPA version\ndidn't suffer from this particular problem, obviously)."
}
],
"lastModified": "2026-09-16T15:18:18.010",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}