FKIE_CVE-2026-99181

Vulnerability from fkie_nvd - Published: 2026-10-28 11:17 - Updated: 2026-10-30 13:21
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: autofs: ignore notification errors from a replaced pipe autofs_notify_daemon() takes a reference to the current notification pipe under wq_mutex, then drops the mutex before writing the request. The write can block while the daemon enters catatonic mode and installs a replacement pipe. If the old pipe's reader is then closed, the delayed write returns -EPIPE and the generic error path enters catatonic mode again. That transition acts on the current superblock state, closes the replacement pipe, and releases the new daemon generation's wait queues. Only enter catatonic mode when the pipe which failed is still the current pipe. Factor the already-locked transition so the identity check and state change are atomic with respect to another replacement. This was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest. An unprivileged UID 65534 lookup filled the old packet pipe before a normal CATATONIC/SETPIPEFD restart. On the unmodified kernel, the new pipe received HUP and both a pending victim lookup and a later lookup failed with ENOENT in two out of two fresh-mount runs. With this change, the new pipe remained active, received an intact 304-byte request, and both victim lookups completed in two out of two runs. Normal lookup and restart-without-a-blocked-writer controls passed. No KASAN, oops, refcount, or lock diagnostic was observed. A source reproducer and complete local logs are available privately on request. The demonstrated impact is limited to denial of a shared autofs service during a legitimate daemon restart. No memory corruption, information leak, privilege escalation, or code execution primitive was observed.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1a177064f501ed4b67873a43aae5d5bdb18b3704
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/35c2c4f3cf1403b058237c44000199a6c9a59273
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/65676cd4203c0e41a94caf54080a7f0a95434bda
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6d2b8ad36e09e07993addd4ce92b578d3b13c8f8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8c8386ffc582155451f074f25759f665e626a850
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/95ba5de229c1875e836f10646c4e6c454d560060
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d3477ebdce74dc3bae404048258e70d7046c208a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fb296391f685d82dbb93621a970fb234cea45280
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/autofs/waitq.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "95ba5de229c1875e836f10646c4e6c454d560060",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "d3477ebdce74dc3bae404048258e70d7046c208a",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "6d2b8ad36e09e07993addd4ce92b578d3b13c8f8",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "35c2c4f3cf1403b058237c44000199a6c9a59273",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "8c8386ffc582155451f074f25759f665e626a850",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "1a177064f501ed4b67873a43aae5d5bdb18b3704",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "fb296391f685d82dbb93621a970fb234cea45280",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            },
            {
              "lessThan": "65676cd4203c0e41a94caf54080a7f0a95434bda",
              "status": "affected",
              "version": "8d7b48e0bc5fa01a818eac713d4cb0763090cd0e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/autofs/waitq.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.28"
            },
            {
              "lessThan": "2.6.28",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.161",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.115",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.59",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "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\nautofs: ignore notification errors from a replaced pipe\n\nautofs_notify_daemon() takes a reference to the current notification\npipe under wq_mutex, then drops the mutex before writing the request. The\nwrite can block while the daemon enters catatonic mode and installs a\nreplacement pipe.\n\nIf the old pipe\u0027s reader is then closed, the delayed write returns -EPIPE\nand the generic error path enters catatonic mode again. That transition\nacts on the current superblock state, closes the replacement pipe, and\nreleases the new daemon generation\u0027s wait queues.\n\nOnly enter catatonic mode when the pipe which failed is still the current\npipe. Factor the already-locked transition so the identity check and state\nchange are atomic with respect to another replacement.\n\nThis was reproduced on v7.3-rc5-337-gff47652a4b66c in a local QEMU guest.\nAn unprivileged UID 65534 lookup filled the old packet pipe before a\nnormal CATATONIC/SETPIPEFD restart. On the unmodified kernel, the new pipe\nreceived HUP and both a pending victim lookup and a later lookup failed\nwith ENOENT in two out of two fresh-mount runs.\n\nWith this change, the new pipe remained active, received an intact\n304-byte request, and both victim lookups completed in two out of two\nruns. Normal lookup and restart-without-a-blocked-writer controls passed.\nNo KASAN, oops, refcount, or lock diagnostic was observed. A source\nreproducer and complete local logs are available privately on request.\n\nThe demonstrated impact is limited to denial of a shared autofs service\nduring a legitimate daemon restart. No memory corruption, information leak,\nprivilege escalation, or code execution primitive was observed."
    }
  ],
  "id": "CVE-2026-99181",
  "lastModified": "2026-10-30T13:21:51.783",
  "metrics": {},
  "published": "2026-10-28T11:17:38.883",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1a177064f501ed4b67873a43aae5d5bdb18b3704"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/35c2c4f3cf1403b058237c44000199a6c9a59273"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/65676cd4203c0e41a94caf54080a7f0a95434bda"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6d2b8ad36e09e07993addd4ce92b578d3b13c8f8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8c8386ffc582155451f074f25759f665e626a850"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/95ba5de229c1875e836f10646c4e6c454d560060"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d3477ebdce74dc3bae404048258e70d7046c208a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fb296391f685d82dbb93621a970fb234cea45280"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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