FKIE_CVE-2025-39905

Vulnerability from fkie_nvd - Published: 2025-10-01 08:15 - Updated: 2026-10-19 21:10
Severity
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: phylink: add lock for serializing concurrent pl->phydev writes with resolver Currently phylink_resolve() protects itself against concurrent phylink_bringup_phy() or phylink_disconnect_phy() calls which modify pl->phydev by relying on pl->state_mutex. The problem is that in phylink_resolve(), pl->state_mutex is in a lock inversion state with pl->phydev->lock. So pl->phydev->lock needs to be acquired prior to pl->state_mutex. But that requires dereferencing pl->phydev in the first place, and without pl->state_mutex, that is racy. Hence the reason for the extra lock. Currently it is redundant, but it will serve a functional purpose once mutex_lock(&phy->lock) will be moved outside of the mutex_lock(&pl->state_mutex) section. Another alternative considered would have been to let phylink_resolve() acquire the rtnl_mutex, which is also held when phylink_bringup_phy() and phylink_disconnect_phy() are called. But since phylink_disconnect_phy() runs under rtnl_lock(), it would deadlock with phylink_resolve() when calling flush_work(&pl->resolve). Additionally, it would have been undesirable because it would have unnecessarily blocked many other call paths as well in the entire kernel, so the smaller-scoped lock was preferred.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/56fe63b05ec84ae6674269d78397cec43a7a295aPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
linux linux_kernel 6.17
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/phy/phylink.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "56fe63b05ec84ae6674269d78397cec43a7a295a",
              "status": "affected",
              "version": "5fd0f1a02e750e2db4038dee60edea669ce5aab1",
              "versionType": "git"
            },
            {
              "lessThan": "0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3",
              "status": "affected",
              "version": "5fd0f1a02e750e2db4038dee60edea669ce5aab1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/phy/phylink.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "96323A8F-8E45-4936-A2A1-7B4CD1FBADB2",
              "versionEndExcluding": "6.16.8",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*",
              "matchCriteriaId": "327D22EF-390B-454C-BD31-2ED23C998A1C",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*",
              "matchCriteriaId": "C730CD9A-D969-4A8E-9522-162AAF7C0EE9",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:*",
              "matchCriteriaId": "39982C4B-716E-4B2F-8196-FA301F47807D",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:*",
              "matchCriteriaId": "340BEEA9-D70D-4290-B502-FBB1032353B1",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:*",
              "matchCriteriaId": "47E4C5C0-079F-4838-971B-8C503D48FCC2",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: phylink: add lock for serializing concurrent pl-\u003ephydev writes with resolver\n\nCurrently phylink_resolve() protects itself against concurrent\nphylink_bringup_phy() or phylink_disconnect_phy() calls which modify\npl-\u003ephydev by relying on pl-\u003estate_mutex.\n\nThe problem is that in phylink_resolve(), pl-\u003estate_mutex is in a lock\ninversion state with pl-\u003ephydev-\u003elock. So pl-\u003ephydev-\u003elock needs to be\nacquired prior to pl-\u003estate_mutex. But that requires dereferencing\npl-\u003ephydev in the first place, and without pl-\u003estate_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(\u0026phy-\u003elock) will be\nmoved outside of the mutex_lock(\u0026pl-\u003estate_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(\u0026pl-\u003eresolve). 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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: phylink: a\u00f1adir un bloqueo para serializar escrituras concurrentes de pl-\u003ephydev con el resolvedor\n\nActualmente, phylink_resolve() se protege contra llamadas concurrentes a phylink_bringup_phy() o phylink_disconnect_phy() que modifican pl-\u003ephydev al depender de pl-\u003estate_mutex.\n\nEl problema es que en phylink_resolve(), pl-\u003estate_mutex est\u00e1 en un estado de inversi\u00f3n de bloqueo con pl-\u003ephydev-\u003elock. As\u00ed que pl-\u003ephydev-\u003elock necesita ser adquirido antes de pl-\u003estate_mutex. Pero eso requiere desreferenciar pl-\u003ephydev en primer lugar, y sin pl-\u003estate_mutex, eso es propenso a condiciones de carrera.\n\nDe ah\u00ed la raz\u00f3n del bloqueo adicional. Actualmente es redundante, pero servir\u00e1 un prop\u00f3sito funcional una vez que mutex_lock(\u0026phy-\u003elock) sea movido fuera de la secci\u00f3n mutex_lock(\u0026pl-\u003estate_mutex).\n\nOtra alternativa considerada habr\u00eda sido permitir que phylink_resolve() adquiera el rtnl_mutex, el cual tambi\u00e9n se mantiene cuando se llaman a phylink_bringup_phy() y phylink_disconnect_phy(). Pero dado que phylink_disconnect_phy() se ejecuta bajo rtnl_lock(), entrar\u00eda en interbloqueo con phylink_resolve() al llamar a flush_work(\u0026pl-\u003eresolve). Adem\u00e1s, habr\u00eda sido indeseable porque habr\u00eda bloqueado innecesariamente muchas otras rutas de llamada tambi\u00e9n en todo el kernel, por lo que se prefiri\u00f3 el bloqueo de alcance m\u00e1s peque\u00f1o."
    }
  ],
  "id": "CVE-2025-39905",
  "lastModified": "2026-10-19T21:10:00.160",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
      },
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 5.9,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2025-39905",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-01-14T19:30:27.795933Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2025-10-01T08:15:33.370",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/0ba5b2f2c381dbec9ed9e4ab3ae5d3e667de0dc3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/56fe63b05ec84ae6674269d78397cec43a7a295a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    },
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-362"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}



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