{"id":"CVE-2026-98563","summary":"net: phylink: record the PHY only once bringup cannot fail","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: phylink: record the PHY only once bringup cannot fail\n\nphylink_bringup_phy() stores the PHY in pl-\u003ephydev before its last\nfallible step: on a MAC whose phylink ops implement LPI,\nphy_eee_rx_clock_stop() can fail with a real MDIO error. The callers\nunwind with phy_detach(), which knows nothing about pl-\u003ephydev, so a\npointer to a PHY that is no longer attached outlives the failed\nconnect.\n\nWhat that costs depends on how the caller got here.\nphylink_connect_phy() goes through phylink_attach_phy(), which refuses\nto attach while pl-\u003ephydev is set, turning a transient MDIO error into\na permanent -EBUSY. The SFP path is worse than that: sfp_sm_probe_phy()\nanswers the failure with phy_device_remove() and phy_device_free(), and\nit assigns sfp-\u003emod_phy only past that error return, so nothing clears\npl-\u003ephydev and it is left pointing at a freed phy_device that\nphylink_resolve() and the ethtool helpers go on reading.\nphylink_fwnode_phy_connect() has no such check, so a later connect\noverwrites the stale pointer and hides the problem. A disconnect does\nnot: phylink_disconnect_phy() hands that pointer to phy_disconnect(),\nand the second phy_detach() on the same PHY drops references the first\none already released.\n\nFound while making a DSA port survive a PHY whose driver arrives after\nthe switch probes: keeping the port across a failed connect and\nretrying is what makes this window reachable.\n\nPublish the pointer after the last call that can fail instead of\nunwinding it afterwards. Nothing between the two points reads\npl-\u003ephydev, and the registration that follows cannot fail:\nphy_request_interrupt() falls back to polling on its own. The PHY-side\nstate keeps the order it had, so no MDIO operation moves relative to\nanother.","modified":"2026-10-19T02:46:38.692769893Z","published":"2026-10-18T15:18:30.158Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98563.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4e7a4af364c2048bafb213bf0ef4a89dcbe1bfd4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/671a68654a9d319d7f0d53a6321db3d9b391bdef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a940003f44e7e441c228151dd212642152700ec8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98563.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98563"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"03abf2a7c65451e663b078b0ed1bfa648cd9380f"},{"fixed":"4e7a4af364c2048bafb213bf0ef4a89dcbe1bfd4"},{"fixed":"671a68654a9d319d7f0d53a6321db3d9b391bdef"},{"fixed":"a940003f44e7e441c228151dd212642152700ec8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98563.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.14.0"},{"fixed":"6.18.55"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98563.json"}}],"schema_version":"1.9.0"}