CVE-2025-40305 (GCVE-0-2025-40305)

Vulnerability from cvelistv5 – Published: 2025-12-08 00:46 – Updated: 2026-05-11 21:46
VLAI
Title
9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN
Summary
In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN p9_read_work() doesn't set Rworksched and doesn't do schedule_work(m->rq) if list_empty(&m->req_list). However, if the pipe is full, we need to read more data and this used to work prior to commit aaec5a95d59615 ("pipe_read: don't wake up the writer if the pipe is still full"). p9_read_work() does p9_fd_read() -> ... -> anon_pipe_read() which (before the commit above) triggered the unnecessary wakeup. This wakeup calls p9_pollwake() which kicks p9_poll_workfn() -> p9_poll_mux(), p9_poll_mux() will notice EPOLLIN and schedule_work(&m->rq). This no longer happens after the optimization above, change p9_fd_request() to use p9_poll_mux() instead of only checking for EPOLLOUT.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7063 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: aaec5a95d59615523db03dd53c2052f0a87beea7 , < 242531004d7de8c159f9bfadebe33fe8060b1046 (git)
Affected: aaec5a95d59615523db03dd53c2052f0a87beea7 , < e8fe3f07a357c39d429e02ca34f740692d88967a (git)
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Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.17.8 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/9p/trans_fd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "242531004d7de8c159f9bfadebe33fe8060b1046",
              "status": "affected",
              "version": "aaec5a95d59615523db03dd53c2052f0a87beea7",
              "versionType": "git"
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              "versionType": "git"
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          "product": "Linux",
          "programFiles": [
            "net/9p/trans_fd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.17.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.8",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN\n\np9_read_work() doesn\u0027t set Rworksched and doesn\u0027t do schedule_work(m-\u003erq)\nif list_empty(\u0026m-\u003ereq_list).\n\nHowever, if the pipe is full, we need to read more data and this used to\nwork prior to commit aaec5a95d59615 (\"pipe_read: don\u0027t wake up the writer\nif the pipe is still full\").\n\np9_read_work() does p9_fd_read() -\u003e ... -\u003e anon_pipe_read() which (before\nthe commit above) triggered the unnecessary wakeup. This wakeup calls\np9_pollwake() which kicks p9_poll_workfn() -\u003e p9_poll_mux(), p9_poll_mux()\nwill notice EPOLLIN and schedule_work(\u0026m-\u003erq).\n\nThis no longer happens after the optimization above, change p9_fd_request()\nto use p9_poll_mux() instead of only checking for EPOLLOUT."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T21:46:46.952Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/242531004d7de8c159f9bfadebe33fe8060b1046"
        },
        {
          "url": "https://git.kernel.org/stable/c/e8fe3f07a357c39d429e02ca34f740692d88967a"
        }
      ],
      "title": "9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40305",
    "datePublished": "2025-12-08T00:46:30.327Z",
    "dateReserved": "2025-04-16T07:20:57.185Z",
    "dateUpdated": "2026-05-11T21:46:46.952Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-40305",
      "date": "2026-10-27",
      "epss": "0.00172",
      "percentile": "0.06563"
    },
    "microsoft_vex": {
      "current_release_date": "2025-12-09T01:01:42.000Z",
      "cve": "CVE-2025-40305",
      "id": "msrc_CVE-2025-40305",
      "initial_release_date": "2025-12-02T00:00:00.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-40305.json",
      "version": "1"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/9p/trans_fd.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "242531004d7de8c159f9bfadebe33fe8060b1046",
                    "status": "affected",
                    "version": "aaec5a95d59615523db03dd53c2052f0a87beea7",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "e8fe3f07a357c39d429e02ca34f740692d88967a",
                    "status": "affected",
                    "version": "aaec5a95d59615523db03dd53c2052f0a87beea7",
                    "versionType": "git"
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                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/9p/trans_fd.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": "6.17.*",
                    "status": "unaffected",
                    "version": "6.17.8",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.18",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\n9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN\n\np9_read_work() doesn\u0027t set Rworksched and doesn\u0027t do schedule_work(m-\u003erq)\nif list_empty(\u0026m-\u003ereq_list).\n\nHowever, if the pipe is full, we need to read more data and this used to\nwork prior to commit aaec5a95d59615 (\"pipe_read: don\u0027t wake up the writer\nif the pipe is still full\").\n\np9_read_work() does p9_fd_read() -\u003e ... -\u003e anon_pipe_read() which (before\nthe commit above) triggered the unnecessary wakeup. This wakeup calls\np9_pollwake() which kicks p9_poll_workfn() -\u003e p9_poll_mux(), p9_poll_mux()\nwill notice EPOLLIN and schedule_work(\u0026m-\u003erq).\n\nThis no longer happens after the optimization above, change p9_fd_request()\nto use p9_poll_mux() instead of only checking for EPOLLOUT."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\n9p/trans_fd: p9_fd_request: activar el hilo rx si EPOLLIN\n\np9_read_work() no establece Rworksched y no ejecuta schedule_work(m -\u003e rq) si list_empty(\u0026m -\u003e req_list).\n\nSin embargo, si la tuber\u00eda est\u00e1 llena, necesitamos leer m\u00e1s datos y esto sol\u00eda funcionar antes del commit aaec5a95d59615 (\u0027pipe_read: no despertar al escritor si la tuber\u00eda todav\u00eda est\u00e1 llena\u0027).\n\np9_read_work() ejecuta p9_fd_read()  -\u003e  ...  -\u003e  anon_pipe_read() lo cual (antes del commit anterior) desencadenaba la activaci\u00f3n innecesaria. Esta activaci\u00f3n llama a p9_pollwake() que activa p9_poll_workfn()  -\u003e  p9_poll_mux(), p9_poll_mux() notar\u00e1 EPOLLIN y schedule_work(\u0026m -\u003e rq).\n\nEsto ya no ocurre despu\u00e9s de la optimizaci\u00f3n anterior, cambiar p9_fd_request() para que use p9_poll_mux() en lugar de solo verificar EPOLLOUT."
          }
        ],
        "id": "CVE-2025-40305",
        "lastModified": "2026-10-14T22:10:00.210",
        "metrics": {},
        "published": "2025-12-08T01:16:02.700",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/242531004d7de8c159f9bfadebe33fe8060b1046"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e8fe3f07a357c39d429e02ca34f740692d88967a"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-30T10:34:33+00:00",
      "cve": "CVE-2025-40305",
      "id": "CVE-2025-40305",
      "initial_release_date": "2025-12-08T00:00:00+00:00",
      "product_status:known_affected": "14",
      "product_status:known_not_affected": "260",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: 9p/trans_fd: p9_fd_request: kick rx thread if EPOLLIN",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-40305.json",
      "version": "3"
    }
  }
}



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