FKIE_CVE-2026-99175

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: fsnotify: prevent mark additions during connector teardown fsnotify_destroy_marks() keeps a reference to its current mark while it drops conn->lock to destroy the mark. This stabilizes the forward-walk cursor, but does not prevent a new mark from being inserted before it. For example, an inotify watch re-added after IN_IGNORED sorts before the old, detached mark for the same group. The walk can miss the replacement and then detach the entire connector from the object. The replacement is still on its group's marks_list and, for inotify, in the watch IDR. The group mutex no longer protects the connector's object from disappearing. An unprivileged fdinfo read racing the final detach can consequently call igrab(NULL): BUG: KASAN: null-ptr-deref in igrab+0x24/0x100 Write of size 4 at addr 0000000000000148 Call Trace: igrab+0x24/0x100 inotify_show_fdinfo+0x1dc/0x5e0 seq_show+0x397/0x690 Set a DESTROYING flag under conn->lock before starting the walk, and reject new marks on that connector with -ENOENT. The existing add-mark error paths undo the temporary group-list entry and the backend's watch allocation. Do not wait for teardown while holding the group mutex, which the destroyer needs. Once the old connector is detached, an add can install a fresh connector as before. This closes the insertion race for all object types using the common connector teardown, without changing the mark reference or SRCU lifetime rules.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/36ebddca56b9d8993d6dc984fdecc748ee1f5e06
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/472589eacdf10b5f9bd10b333957ed5291b2544b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/587d80966dcce2824f13fd32dab83bf882acf66f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/61133f15773b907bada651a02d9c6d38eae37c48
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d28a460a2237220d9ccbdd3baac6eaead44e96cb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/da2f9aa89ef1b1fe7a7c6e1a8ddacd9c975e86aa
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f7def717c06aea7004905e4d1568c3691ef9825d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/notify/mark.c",
            "include/linux/fsnotify_backend.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f7def717c06aea7004905e4d1568c3691ef9825d",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "da2f9aa89ef1b1fe7a7c6e1a8ddacd9c975e86aa",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "587d80966dcce2824f13fd32dab83bf882acf66f",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "d28a460a2237220d9ccbdd3baac6eaead44e96cb",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "61133f15773b907bada651a02d9c6d38eae37c48",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "472589eacdf10b5f9bd10b333957ed5291b2544b",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            },
            {
              "lessThan": "36ebddca56b9d8993d6dc984fdecc748ee1f5e06",
              "status": "affected",
              "version": "6b3f05d24d355f50f3d9814304650fcab0efb482",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/notify/mark.c",
            "include/linux/fsnotify_backend.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.12"
            },
            {
              "lessThan": "4.12",
              "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\nfsnotify: prevent mark additions during connector teardown\n\nfsnotify_destroy_marks() keeps a reference to its current mark while it\ndrops conn-\u003elock to destroy the mark. This stabilizes the forward-walk\ncursor, but does not prevent a new mark from being inserted before it.\nFor example, an inotify watch re-added after IN_IGNORED sorts before the\nold, detached mark for the same group. The walk can miss the replacement\nand then detach the entire connector from the object.\n\nThe replacement is still on its group\u0027s marks_list and, for inotify, in\nthe watch IDR. The group mutex no longer protects the connector\u0027s object\nfrom disappearing. An unprivileged fdinfo read racing the final detach\ncan consequently call igrab(NULL):\n\n  BUG: KASAN: null-ptr-deref in igrab+0x24/0x100\n  Write of size 4 at addr 0000000000000148\n  Call Trace:\n   igrab+0x24/0x100\n   inotify_show_fdinfo+0x1dc/0x5e0\n   seq_show+0x397/0x690\n\nSet a DESTROYING flag under conn-\u003elock before starting the walk, and\nreject new marks on that connector with -ENOENT. The existing add-mark\nerror paths undo the temporary group-list entry and the backend\u0027s watch\nallocation. Do not wait for teardown while holding the group mutex,\nwhich the destroyer needs. Once the old connector is detached, an add\ncan install a fresh connector as before.\n\nThis closes the insertion race for all object types using the common\nconnector teardown, without changing the mark reference or SRCU lifetime\nrules."
    }
  ],
  "id": "CVE-2026-99175",
  "lastModified": "2026-10-30T13:21:51.120",
  "metrics": {},
  "published": "2026-10-28T11:17:38.150",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/36ebddca56b9d8993d6dc984fdecc748ee1f5e06"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/472589eacdf10b5f9bd10b333957ed5291b2544b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/587d80966dcce2824f13fd32dab83bf882acf66f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/61133f15773b907bada651a02d9c6d38eae37c48"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d28a460a2237220d9ccbdd3baac6eaead44e96cb"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/da2f9aa89ef1b1fe7a7c6e1a8ddacd9c975e86aa"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f7def717c06aea7004905e4d1568c3691ef9825d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.