{"cve":"CVE-2025-39905","nvd":{"published":"2025-10-01T08:15:33.370","modified":"2026-10-19T21:10:00.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: phylink: add lock for serializing concurrent pl->phydev writes with resolver\n\nCurrently phylink_resolve() protects itself against concurrent\nphylink_bringup_phy() or phylink_disconnect_phy() calls which modify\npl->phydev by relying on pl->state_mutex.\n\nThe problem is that in phylink_resolve(), pl->state_mutex is in a lock\ninversion state with pl->phydev->lock. So pl->phydev->lock needs to be\nacquired prior to pl->state_mutex. But that requires dereferencing\npl->phydev in the first place, and without pl->state_mutex, that is\nracy.\n\nHence the reason for the extra lock. Currently it is redundant, but it\nwill serve a functional purpose once mutex_lock(&phy->lock) will be\nmoved outside of the mutex_lock(&pl->state_mutex) section.\n\nAnother alternative considered would have been to let phylink_resolve()\nacquire the rtnl_mutex, which is also held when phylink_bringup_phy()\nand phylink_disconnect_phy() are called. But since phylink_disconnect_phy()\nruns under rtnl_lock(), it would deadlock with phylink_resolve() when\ncalling flush_work(&pl->resolve). Additionally, it would have been\nundesirable because it would have unnecessarily blocked many other call\npaths as well in the entire kernel, so the smaller-scoped lock was\npreferred.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.0},"cwes":["CWE-362"],"references":["https://git.kernel.org/stable/c/0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3","https://git.kernel.org/stable/c/56fe63b05ec84ae6674269d78397cec43a7a295a"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-39905","score":0.00111,"percentile":0.01339,"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."]}