{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-39915", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.147Z", "datePublished": "2025-10-01T07:44:37.884Z", "dateUpdated": "2026-05-11T21:38:52.462Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T21:38:52.462Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: phy: transfer phy_config_inband() locking responsibility to phylink\n\nProblem description\n===================\n\nLockdep reports a possible circular locking dependency (AB/BA) between\n&pl->state_mutex and &phy->lock, as follows.\n\nphylink_resolve() // acquires &pl->state_mutex\n-> phylink_major_config()\n -> phy_config_inband() // acquires &pl->phydev->lock\n\nwhereas all the other call sites where &pl->state_mutex and\n&pl->phydev->lock have the locking scheme reversed. Everywhere else,\n&pl->phydev->lock is acquired at the top level, and &pl->state_mutex at\nthe lower level. A clear example is phylink_bringup_phy().\n\nThe outlier is the newly introduced phy_config_inband() and the existing\nlock order is the correct one. To understand why it cannot be the other\nway around, it is sufficient to consider phylink_phy_change(), phylink's\ncallback from the PHY device's phy->phy_link_change() virtual method,\ninvoked by the PHY state machine.\n\nphy_link_up() and phy_link_down(), the (indirect) callers of\nphylink_phy_change(), are called with &phydev->lock acquired.\nThen phylink_phy_change() acquires its own &pl->state_mutex, to\nserialize changes made to its pl->phy_state and pl->link_config.\nSo all other instances of &pl->state_mutex and &phydev->lock must be\nconsistent with this order.\n\nProblem impact\n==============\n\nI think the kernel runs a serious deadlock risk if an existing\nphylink_resolve() thread, which results in a phy_config_inband() call,\nis concurrent with a phy_link_up() or phy_link_down() call, which will\ndeadlock on &pl->state_mutex in phylink_phy_change(). Practically\nspeaking, the impact may be limited by the slow speed of the medium\nauto-negotiation protocol, which makes it unlikely for the current state\nto still be unresolved when a new one is detected, but I think the\nproblem is there. Nonetheless, the problem was discovered using lockdep.\n\nProposed solution\n=================\n\nPractically speaking, the phy_config_inband() requirement of having\nphydev->lock acquired must transfer to the caller (phylink is the only\ncaller). There, it must bubble up until immediately before\n&pl->state_mutex is acquired, for the cases where that takes place.\n\nSolution details, considerations, notes\n=======================================\n\nThis is the phy_config_inband() call graph:\n\n sfp_upstream_ops :: connect_phy()\n |\n v\n phylink_sfp_connect_phy()\n |\n v\n phylink_sfp_config_phy()\n |\n | sfp_upstream_ops :: module_insert()\n | |\n | v\n | phylink_sfp_module_insert()\n | |\n | | sfp_upstream_ops :: module_start()\n | | |\n | | v\n | | phylink_sfp_module_start()\n | | |\n | v v\n | phylink_sfp_config_optical()\n phylink_start() | |\n | phylink_resume() v v\n | | phylink_sfp_set_config()\n | | |\n v v v\n phylink_mac_initial_config()\n | phylink_resolve()\n | | phylink_ethtool_ksettings_set()\n v v v\n phylink_major_config()\n |\n v\n phy_config_inband()\n\nphylink_major_config() caller #1, phylink_mac_initial_config(), does not\nacquire &pl->state_mutex nor do its callers. It must acquire\n&pl->phydev->lock prior to calling phylink_major_config().\n\nphylink_major_config() caller #2, phylink_resolve() acquires\n&pl->state_mutex, thus also needs to acquire &pl->phydev->lock.\n\nphylink_major_config() caller #3, phylink_ethtool_ksettings_set(), is\ncompletely uninteresting, because it only call\n---truncated---" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/phy/phy.c", "drivers/net/phy/phylink.c" ], "versions": [ { "version": "5fd0f1a02e750e2db4038dee60edea669ce5aab1", "lessThan": "052ac41c379c8b87629808be612a482b2d0ae283", "status": "affected", "versionType": "git" }, { "version": "5fd0f1a02e750e2db4038dee60edea669ce5aab1", "lessThan": "e2a10daba84968f6b5777d150985fd7d6abc9c84", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/phy/phy.c", "drivers/net/phy/phylink.c" ], "versions": [ { "version": "6.14", "status": "affected" }, { "version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.8", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.16.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/052ac41c379c8b87629808be612a482b2d0ae283" }, { "url": "https://git.kernel.org/stable/c/e2a10daba84968f6b5777d150985fd7d6abc9c84" } ], "title": "net: phy: transfer phy_config_inband() locking responsibility to phylink", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2025-39915", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2026-01-14T17:42:55.510925Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-667", "description": "CWE-667 Improper Locking" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-14T17:52:47.502Z" } } ] } }