{"cve":"CVE-2025-71074","nvd":{"published":"2026-01-13T16:16:06.860","modified":"2026-10-21T13:18:25.130","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfunctionfs: fix the open/removal races\n\nffs_epfile_open() can race with removal, ending up with file->private_data\npointing to freed object.\n\nThere is a total count of opened files on functionfs (both ep0 and\ndynamic ones) and when it hits zero, dynamic files get removed.\nUnfortunately, that removal can happen while another thread is\nin ffs_epfile_open(), but has not incremented the count yet.\nIn that case open will succeed, leaving us with UAF on any subsequent\nread() or write().\n\nThe root cause is that ffs->opened is misused; atomic_dec_and_test() vs.\natomic_add_return() is not a good idea, when object remains visible all\nalong.\n\nTo untangle that\n\t* serialize openers on ffs->mutex (both for ep0 and for dynamic files)\n\t* have dynamic ones use atomic_inc_not_zero() and fail if we had\nzero ->opened; in that case the file we are opening is doomed.\n\t* have the inodes of dynamic files marked on removal (from the\ncallback of simple_recursive_removal()) - clear ->i_private there.\n\t* have open of dynamic ones verify they hadn't been already removed,\nalong with checking that state is FFS_ACTIVE.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","score":4.7},"cwes":["CWE-362"],"references":["https://git.kernel.org/stable/c/585a656283c954337036422afcd9cb70dd4135e7","https://git.kernel.org/stable/c/75240e5e51c6e6d67a3039384125fa54259a3926","https://git.kernel.org/stable/c/e5bf5ee266633cb18fff6f98f0b7d59a62819eee"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2025-71074","score":0.00131,"percentile":0.02652,"date":"2026-10-25"},"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."]}