FKIE_CVE-2026-93795

Vulnerability from fkie_nvd - Published: 2026-09-24 17:17 - Updated: 2026-09-25 13:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-cgroup: fix leaks and online flag on radix_tree_insert failure When radix_tree_insert() fails in blkg_create(), the error path has two issues: 1. blkg->online is set to true unconditionally, even when the blkg was never fully inserted. Move the assignment inside the success block. 2. The error path calls blkg_put() without first calling percpu_ref_kill(). Because the refcount is still in percpu mode, percpu_ref_put() only does this_cpu_sub() without checking for zero, so blkg_release() is never triggered. This permanently leaks the blkg memory, its percpu iostat, policy data, the parent blkg reference, and the cgroup css reference — the latter preventing the cgroup from ever being destroyed. Fix by replacing blkg_put() with percpu_ref_kill(), matching the pattern used in blkg_destroy().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4c0d150fb98ea40760611979f4e664c244b20966
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6e85f02d45b5977c0326a8d854c6db878aa6b34a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/dbbca20764382b4d411ec2918f4e278ffe547acc
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/blk-cgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6e85f02d45b5977c0326a8d854c6db878aa6b34a",
              "status": "affected",
              "version": "7fcf2b033b84e261dca283bc2911aaea4b07b525",
              "versionType": "git"
            },
            {
              "lessThan": "4c0d150fb98ea40760611979f4e664c244b20966",
              "status": "affected",
              "version": "7fcf2b033b84e261dca283bc2911aaea4b07b525",
              "versionType": "git"
            },
            {
              "lessThan": "dbbca20764382b4d411ec2918f4e278ffe547acc",
              "status": "affected",
              "version": "7fcf2b033b84e261dca283bc2911aaea4b07b525",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "block/blk-cgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.0"
            },
            {
              "lessThan": "5.0",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nblk-cgroup: fix leaks and online flag on radix_tree_insert failure\n\nWhen radix_tree_insert() fails in blkg_create(), the error path has two\nissues:\n\n1. blkg-\u003eonline is set to true unconditionally, even when the blkg was\n   never fully inserted.  Move the assignment inside the success block.\n\n2. The error path calls blkg_put() without first calling\n   percpu_ref_kill().  Because the refcount is still in percpu mode,\n   percpu_ref_put() only does this_cpu_sub() without checking for zero,\n   so blkg_release() is never triggered.  This permanently leaks the\n   blkg memory, its percpu iostat, policy data, the parent blkg\n   reference, and the cgroup css reference \u2014 the latter preventing the\n   cgroup from ever being destroyed.\n\nFix by replacing blkg_put() with percpu_ref_kill(), matching the pattern\nused in blkg_destroy()."
    }
  ],
  "id": "CVE-2026-93795",
  "lastModified": "2026-09-25T13:17:20.097",
  "metrics": {},
  "published": "2026-09-24T17:17:12.270",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4c0d150fb98ea40760611979f4e664c244b20966"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6e85f02d45b5977c0326a8d854c6db878aa6b34a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/dbbca20764382b4d411ec2918f4e278ffe547acc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.