{"cve":"CVE-2025-39877","nvd":{"published":"2025-09-23T06:15:47.230","modified":"2026-10-19T21:10:00.160","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/sysfs: fix use-after-free in state_show()\n\nstate_show() reads kdamond->damon_ctx without holding damon_sysfs_lock. \nThis allows a use-after-free race:\n\nCPU 0                         CPU 1\n-----                         -----\nstate_show()                  damon_sysfs_turn_damon_on()\nctx = kdamond->damon_ctx;     mutex_lock(&damon_sysfs_lock);\n                              damon_destroy_ctx(kdamond->damon_ctx);\n                              kdamond->damon_ctx = NULL;\n                              mutex_unlock(&damon_sysfs_lock);\ndamon_is_running(ctx);        /* ctx is freed */\nmutex_lock(&ctx->kdamond_lock); /* UAF */\n\n(The race can also occur with damon_sysfs_kdamonds_rm_dirs() and\ndamon_sysfs_kdamond_release(), which free or replace the context under\ndamon_sysfs_lock.)\n\nFix by taking damon_sysfs_lock before dereferencing the context, mirroring\nthe locking used in pid_show().\n\nThe bug has existed since state_show() first accessed kdamond->damon_ctx.","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/26d29b2ac87a2989071755f9828ebf839b560d4c","https://git.kernel.org/stable/c/3260a3f0828e06f5f13fac69fb1999a6d60d9cff","https://git.kernel.org/stable/c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50e","https://git.kernel.org/stable/c/4e87f461d61959647464a94d11ae15c011be58ce","https://git.kernel.org/stable/c/60d7a3d2b985a395318faa1d88da6915fad11c19"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39877","score":0.00154,"percentile":0.04439,"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."]}