CVE-2026-90138
In the Linux kernel, the following vulnerability has been resolved:
vsock: don't check the listener's sk_err in vsock_accept()
Basically, it creates a socket (r0) and triggers a self-connect after binding it. This self-connect fails with EPROTO because it loops back to r0 while the socket is still in the TCP_SYN_SENT state, causing it to be incorrectly dispatched to the connecting-client path. The unexpected packet type encountered there sets sk_err to EPROTO.
After that, it invokes a listen() call on the same socket. This listen() call succeeds because the kernel's listening path never inspects or clears sk_err.
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Then, a new socket (r1) is created as a normal client and connects to r0. However, vsock_accept() rejects this incoming connection because the listener's sk_err still holds the EPROTO error from the earlier failed self-connect.
This rejection causes the child socket created for r1's connection to never be freed on virtio or hyperv transports; only the VMCI transport implements pending_work to revisit and clean up a rejected socket.
For a non-blocking connect(), vsock_connect() may return -EINPROGRESS immediately, and vsock_connect_timeout() can later set sk->sk_err asynchronously.
Since no vsock transport ever sets sk_err on a socket while it is in TCP_LISTEN state, checking it in vsock_accept() serves no purpose and only carries forward errors left behind by earlier, unrelated connection attempts on the same socket. Remove the checks so accept() no longer rejects valid incoming connections because of a stale error, which also avoids the resource leak described above.
Detalles técnicos trazas, registros y código del informe original
Syzbot reported an issue which can be reproduced with these steps:
r0 = socket(AF_VSOCK, SOCK_STREAM, 0)
bind(r0, {VMADDR_CID_ANY, PORT})
connect(r0, {VMADDR_CID_LOCAL, PORT}) -> -1, EPROTO (self-connect)
listen(r0, backlog) -> 0
r1 = socket(AF_VSOCK, SOCK_STREAM, 0)
connect(r1, {VMADDR_CID_LOCAL, PORT}) -> 0
accept(r0) -> -1, EPROTO (stale sk_err)CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- 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).
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-2026-90138",
"cveTags": [],
"metrics": {},
"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": "d021c344051af91f42c5ba9fdedc176740cbd238",
"lessThan": "c5a75d37c21e558cc6fad1597e732ead30745eed",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"version": "d021c344051af91f42c5ba9fdedc176740cbd238",
"lessThan": "491b368a0c6e5f28b615a50b0d384f5c25fde2a7",
"versionType": "git"
},
{
"status": "affected",
"version": "d021c344051af91f42c5ba9fdedc176740cbd238",
"lessThan": "b8c899cf5e7be29840a172c183dedd8d3e7a0287",
"versionType": "git"
}
],
"programFiles": [
"net/vmw_vsock/af_vsock.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.52",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.6",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/vmw_vsock/af_vsock.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-17T17:17:06.407",
"references": [
{
"url": "https://git.kernel.org/stable/c/36e5fa009f98a4edbe1783ac11c0df672b224742",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/491b368a0c6e5f28b615a50b0d384f5c25fde2a7",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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{
"url": "https://git.kernel.org/stable/c/b8c899cf5e7be29840a172c183dedd8d3e7a0287",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c5a75d37c21e558cc6fad1597e732ead30745eed",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock: don't check the listener's sk_err in vsock_accept()\n\nSyzbot reported an issue which can be reproduced with these steps:\n\tr0 = socket(AF_VSOCK, SOCK_STREAM, 0)\n\tbind(r0, {VMADDR_CID_ANY, PORT})\n\tconnect(r0, {VMADDR_CID_LOCAL, PORT}) -> -1, EPROTO (self-connect)\n\tlisten(r0, backlog) -> 0\n\tr1 = socket(AF_VSOCK, SOCK_STREAM, 0)\n\tconnect(r1, {VMADDR_CID_LOCAL, PORT}) -> 0\n\taccept(r0) -> -1, EPROTO (stale sk_err)\n\nBasically, it creates a socket (r0) and triggers a self-connect after\nbinding it. This self-connect fails with EPROTO because it loops back\nto r0 while the socket is still in the TCP_SYN_SENT state, causing it\nto be incorrectly dispatched to the connecting-client path. The\nunexpected packet type encountered there sets sk_err to EPROTO.\n\nAfter that, it invokes a listen() call on the same socket. This\nlisten() call succeeds because the kernel's listening path never\ninspects or clears sk_err. Then, a new socket (r1) is created as a\nnormal client and connects to r0. However, vsock_accept() rejects this\nincoming connection because the listener's sk_err still holds the\nEPROTO error from the earlier failed self-connect.\n\nThis rejection causes the child socket created for r1's connection to\nnever be freed on virtio or hyperv transports; only the VMCI transport\nimplements pending_work to revisit and clean up a rejected socket.\n\nFor a non-blocking connect(), vsock_connect() may return -EINPROGRESS\nimmediately, and vsock_connect_timeout() can later set sk->sk_err\nasynchronously.\n\nSince no vsock transport ever sets sk_err on a socket while it is in\nTCP_LISTEN state, checking it in vsock_accept() serves no purpose and\nonly carries forward errors left behind by earlier, unrelated\nconnection attempts on the same socket. Remove the checks so accept()\nno longer rejects valid incoming connections because of a stale\nerror, which also avoids the resource leak described above."
}
],
"lastModified": "2026-09-17T17:17:06.407",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}