{"id":"CVE-2026-98563","title":"net: phylink: record the PHY only once bringup cannot fail","summary":"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->phydev before its last\nfallible step: on a MAC whose phylink ops…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 03abf2a7c65451e663b078b0ed1bfa648cd9380f < 4e7a4af364c2048bafb213bf0ef4a89dcbe1bfd4","Linux >= 03abf2a7c65451e663b078b0ed1bfa648cd9380f < 671a68654a9d319d7f0d53a6321db3d9b391bdef","Linux >= 03abf2a7c65451e663b078b0ed1bfa648cd9380f < a940003f44e7e441c228151dd212642152700ec8","Linux 6.14"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:18:30.158Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98563","references":[{"url":"https://git.kernel.org/stable/c/4e7a4af364c2048bafb213bf0ef4a89dcbe1bfd4"},{"url":"https://git.kernel.org/stable/c/671a68654a9d319d7f0d53a6321db3d9b391bdef"},{"url":"https://git.kernel.org/stable/c/a940003f44e7e441c228151dd212642152700ec8"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.260Z","slug":"CVE-2026-98563","body":"## Overview\n\nIn 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->phydev 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->phydev, 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->phydev 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->mod_phy only past that error return, so nothing clears\npl->phydev 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->phydev, 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.\n\n## Affected\n\n- `Linux >= 03abf2a7c65451e663b078b0ed1bfa648cd9380f < 4e7a4af364c2048bafb213bf0ef4a89dcbe1bfd4`\n- `Linux >= 03abf2a7c65451e663b078b0ed1bfa648cd9380f < 671a68654a9d319d7f0d53a6321db3d9b391bdef`\n- `Linux >= 03abf2a7c65451e663b078b0ed1bfa648cd9380f < a940003f44e7e441c228151dd212642152700ec8`\n- `Linux 6.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}