{"cve":"CVE-2024-39463","nvd":{"published":"2024-06-25T15:15:14.760","modified":"2026-06-17T07:41:57.930","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\n9p: add missing locking around taking dentry fid list\n\nFix a use-after-free on dentry's d_fsdata fid list when a thread\nlooks up a fid through dentry while another thread unlinks it:\n\nUAF thread:\nrefcount_t: addition on 0; use-after-free.\n p9_fid_get linux/./include/net/9p/client.h:262\n v9fs_fid_find+0x236/0x280 linux/fs/9p/fid.c:129\n v9fs_fid_lookup_with_uid linux/fs/9p/fid.c:181\n v9fs_fid_lookup+0xbf/0xc20 linux/fs/9p/fid.c:314\n v9fs_vfs_getattr_dotl+0xf9/0x360 linux/fs/9p/vfs_inode_dotl.c:400\n vfs_statx+0xdd/0x4d0 linux/fs/stat.c:248\n\nFreed by:\n p9_fid_destroy (inlined)\n p9_client_clunk+0xb0/0xe0 linux/net/9p/client.c:1456\n p9_fid_put linux/./include/net/9p/client.h:278\n v9fs_dentry_release+0xb5/0x140 linux/fs/9p/vfs_dentry.c:55\n v9fs_remove+0x38f/0x620 linux/fs/9p/vfs_inode.c:518\n vfs_unlink+0x29a/0x810 linux/fs/namei.c:4335\n\nThe problem is that d_fsdata was not accessed under d_lock, because\nd_release() normally is only called once the dentry is otherwise no\nlonger accessible but since we also call it explicitly in v9fs_remove\nthat lock is required:\nmove the hlist out of the dentry under lock then unref its fids once\nthey are no longer accessible.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/3bb6763a8319170c2d41c4232c8e7e4c37dcacfb","https://git.kernel.org/stable/c/c898afdc15645efb555acb6d85b484eb40a45409","https://git.kernel.org/stable/c/cb299cdba09f46f090b843d78ba26b667d50a456","https://git.kernel.org/stable/c/f0c5c944c6d8614c19e6e9a97fd2011dcd30e8f5","https://git.kernel.org/stable/c/fe17ebf22feb4ad7094d597526d558a49aac92b4"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:52:00.836172422+00:00"},"epss":{"cve":"CVE-2024-39463","score":0.00253,"percentile":0.16825,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}