{"id":"CVE-2026-89707","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-89707","summary":"nfsd: release path refs on follow_down() error","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: release path refs on follow_down() error\n\nnfsd_cross_mnt() initializes a local struct path with mntget() and\ndget() before calling follow_down(). On a negative return the error\narm jumps to out without releasing those references:\n\n    err = follow_down(&path, follow_flags);\n    if (err < 0)\n            goto out;\n\nfollow_down() never drops the caller's entry-time refs on any error\nsub-case; for example a pre-cross d_manage() failure leaves path\nuntouched, so the mntget()/dget() taken on entry survive the call.\n\nEvery other early-exit arm in nfsd_cross_mnt() (other-namespace\nreturn, IS_ERR(exp2), and the success tail after the swap) already\ncalls path_put(&path); the err < 0 arm is the lone omission. The\nleak inflates mnt_count and d_count on each failed cross-mount,\nblocking umount and pinning dentries against the shrinker, and is\nreachable by any authenticated NFS client through nfsd_lookup_dentry\nor the NFSv4 READDIR encode path.\n\nFix by calling path_put(&path) before the goto out in the err < 0\narm so the entry-time refs are released on all follow_down() error\nreturns.","published":"2026-09-11T19:46:23.293Z","modified":"2026-09-14T03:46:28.806747018Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.12.109"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89707.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89707"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T03:46:28.806747018Z"}}