{"id":"CVE-2026-90138","title":"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\tb…","summary":"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\tb…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < c5a75d37c21e558cc6fad1597e732ead30745eed","Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 36e5fa009f98a4edbe1783ac11c0df672b224742","Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < 491b368a0c6e5f28b615a50b0d384f5c25fde2a7","Linux >= d021c344051af91f42c5ba9fdedc176740cbd238 < b8c899cf5e7be29840a172c183dedd8d3e7a0287","Linux 3.9"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:06.407","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90138","references":[{"url":"https://git.kernel.org/stable/c/36e5fa009f98a4edbe1783ac11c0df672b224742","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/491b368a0c6e5f28b615a50b0d384f5c25fde2a7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b8c899cf5e7be29840a172c183dedd8d3e7a0287","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c5a75d37c21e558cc6fad1597e732ead30745eed","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.878Z","epss":0.002,"epssPercentile":0.10104,"slug":"CVE-2026-90138","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}