{"cve":"CVE-2025-21655","nvd":{"published":"2025-01-20T14:15:27.027","modified":"2026-10-15T02:17:25.550","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/eventfd: ensure io_eventfd_signal() defers another RCU period\n\nio_eventfd_do_signal() is invoked from an RCU callback, but when\ndropping the reference to the io_ev_fd, it calls io_eventfd_free()\ndirectly if the refcount drops to zero. This isn't correct, as any\npotential freeing of the io_ev_fd should be deferred another RCU grace\nperiod.\n\nJust call io_eventfd_put() rather than open-code the dec-and-test and\nfree, which will correctly defer it another RCU grace period.","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-416"],"references":["https://git.kernel.org/stable/c/6b63308c28987c6010b1180c72a6db4df6c68033","https://git.kernel.org/stable/c/8efff2aa2d95dc437ab67c5b4a9f1d3f367baa10","https://git.kernel.org/stable/c/a7085c3ae43b86d4b3d1b8275e6a67f14257e3b7","https://git.kernel.org/stable/c/c9a40292a44e78f71258b8522655bffaf5753bdb","https://project-zero.issues.chromium.org/issues/388499293"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:58:41.599736885+00:00"},"epss":{"cve":"CVE-2025-21655","score":0.00253,"percentile":0.16598,"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."]}