Vulnerability-Lookup

GHSA-PCCJ-HX6X-MQG3

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31

Details

In the Linux kernel, the following vulnerability has been resolved:

ceph: lock mutex in ceph_mds_check_access()

MDS session OPEN handling replaces mdsc->s_cap_auths under mdsc->mutex, freeing the previous array and its strings.

ceph_mds_check_access() traverses this array without holding the mutex. A concurrent session reopen can therefore free the array while it is being inspected, resulting in a use-after-free like this:

Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9 [...] Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE [..] pc : ceph_mds_check_access+0xd4/0x550 lr : ceph_mds_check_access+0xc8/0x550 [...] Call trace: ceph_mds_check_access+0xd4/0x550 (P) ceph_atomic_open+0x138/0xbe8 path_openat+0xa24/0xfa8 do_filp_open+0x94/0x158 do_sys_openat2+0x88/0xf8

Severity

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89990"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:10Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: lock mutex in ceph_mds_check_access()\n\nMDS session OPEN handling replaces mdsc-\u003es_cap_auths under\nmdsc-\u003emutex, freeing the previous array and its strings.\n\nceph_mds_check_access() traverses this array without holding the\nmutex.  A concurrent session reopen can therefore free the array while\nit is being inspected, resulting in a use-after-free like this:\n\n  Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9\n  [...]\n  Internal error: Oops: 0000000096000004 [#1]  SMP\n  Modules linked in:\n  CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE\n  [..]\n  pc : ceph_mds_check_access+0xd4/0x550\n  lr : ceph_mds_check_access+0xc8/0x550\n  [...]\n  Call trace:\n   ceph_mds_check_access+0xd4/0x550 (P)\n   ceph_atomic_open+0x138/0xbe8\n   path_openat+0xa24/0xfa8\n   do_filp_open+0x94/0x158\n   do_sys_openat2+0x88/0xf8",
  "id": "GHSA-pccj-hx6x-mqg3",
  "modified": "2026-09-16T15:31:04Z",
  "published": "2026-09-16T12:30:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89990"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/729c1ff670ece6f3d4b1738365a0b2f90d487523"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a61c6ae1dae2611082b831b4aaa780878099c012"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/df1a97d5313fccadb08390306d49b194fb027392"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89990 (GCVE-0-2026-89990)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:33 – Updated: 2026-09-16 14:41

Title

ceph: lock mutex in ceph_mds_check_access()

Summary

In the Linux kernel, the following vulnerability has been resolved: ceph: lock mutex in ceph_mds_check_access() MDS session OPEN handling replaces mdsc->s_cap_auths under mdsc->mutex, freeing the previous array and its strings. ceph_mds_check_access() traverses this array without holding the mutex. A concurrent session reopen can therefore free the array while it is being inspected, resulting in a use-after-free like this: Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9 [...] Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE [..] pc : ceph_mds_check_access+0xd4/0x550 lr : ceph_mds_check_access+0xc8/0x550 [...] Call trace: ceph_mds_check_access+0xd4/0x550 (P) ceph_atomic_open+0x138/0xbe8 path_openat+0xa24/0xfa8 do_filp_open+0x94/0x158 do_sys_openat2+0x88/0xf8

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/729c1ff670ece6f3d…
https://git.kernel.org/stable/c/ca5bfea2045ef2eb3…
https://git.kernel.org/stable/c/df1a97d5313fccadb…
https://git.kernel.org/stable/c/a61c6ae1dae261108…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 596afb0b8933ba6ed7227adcc538db26feb25c74 , < 729c1ff670ece6f3d4b1738365a0b2f90d487523 (git) Affected: 596afb0b8933ba6ed7227adcc538db26feb25c74 , < ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3 (git) Affected: 596afb0b8933ba6ed7227adcc538db26feb25c74 , < df1a97d5313fccadb08390306d49b194fb027392 (git) Affected: 596afb0b8933ba6ed7227adcc538db26feb25c74 , < a61c6ae1dae2611082b831b4aaa780878099c012 (git)
Linux	Linux	Affected: 6.10 Unaffected: 0 , < 6.10 (semver) Unaffected: 6.12.110 , ≤ 6.12.* (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.5 , ≤ 7.2.* (semver) Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/mds_client.c",
            "fs/ceph/mds_client.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "729c1ff670ece6f3d4b1738365a0b2f90d487523",
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              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "versionType": "git"
            },
            {
              "lessThan": "ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3",
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "versionType": "git"
            },
            {
              "lessThan": "df1a97d5313fccadb08390306d49b194fb027392",
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ceph/mds_client.c",
            "fs/ceph/mds_client.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc2",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nceph: lock mutex in ceph_mds_check_access()\n\nMDS session OPEN handling replaces mdsc-\u003es_cap_auths under\nmdsc-\u003emutex, freeing the previous array and its strings.\n\nceph_mds_check_access() traverses this array without holding the\nmutex.  A concurrent session reopen can therefore free the array while\nit is being inspected, resulting in a use-after-free like this:\n\n  Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9\n  [...]\n  Internal error: Oops: 0000000096000004 [#1]  SMP\n  Modules linked in:\n  CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE\n  [..]\n  pc : ceph_mds_check_access+0xd4/0x550\n  lr : ceph_mds_check_access+0xc8/0x550\n  [...]\n  Call trace:\n   ceph_mds_check_access+0xd4/0x550 (P)\n   ceph_atomic_open+0x138/0xbe8\n   path_openat+0xa24/0xfa8\n   do_filp_open+0x94/0x158\n   do_sys_openat2+0x88/0xf8"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - handle_session() frees mdsc-\u003es_cap_auths on CEPH_SESSION_OPEN delivered over the Ceph messenger TCP session (mds_dispatch, CEPH_MSG_CLIENT_SESSION). CephFS re-exported via nfsd/ksmbd also lets a remote client reach the unlocked walker through ceph_atomic_open.\nAC:L - A malicious MDS may send CEPH_SESSION_OPEN even on an already-open session, freeing and replacing s_cap_auths under mdsc-\u003emutex at will. Concurrent open/unlink/setattr, including nfsd/ksmbd on a CephFS export, walk that array without the mutex; the MDS can retry while those operations are in flight.\nPR:N - The attacker is the remote MDS peer, or an NFS/SMB client of a CephFS re-export, and needs no Linux UID, capability, or init-namespace root on the victim host, matching other MDS-driven CephFS client CVEs such as CVE-2026-89651.\nUI:N - Once CephFS is mounted, as is standard in Rook, Kubernetes, and OpenStack, SESSION_OPEN and VFS/nfsd opens run without any further interactive victim action such as mounting media or opening a user-supplied file at exploit time.\nS:U - The use-after-free corrupts kernel heap on the CephFS client host and remains in that kernel\u0027s security authority; it is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - ceph_mds_check_access() and ceph_mds_auth_match() dereference the freed s_cap_auths array and its match.path, gids, and fs_name strings; a use-after-free of those objects enables arbitrary kernel read via heap reuse and is High per kernel UAF guidance.\nI:H - The same UAF is heap-sprayable with attacker-controlled SESSION_OPEN allocations (cap_auths_num and string lengths), yielding write and control-flow primitives; kernel guidance scores use-after-free integrity as High.\nA:H - The reported oops is a kernel paging fault in ceph_mds_check_access from ceph_atomic_open on the freed array; repeating SESSION_OPEN while the walker runs can oops or panic the client, which is High availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:41:05.472Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/729c1ff670ece6f3d4b1738365a0b2f90d487523"
        },
        {
          "url": "https://git.kernel.org/stable/c/ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3"
        },
        {
          "url": "https://git.kernel.org/stable/c/df1a97d5313fccadb08390306d49b194fb027392"
        },
        {
          "url": "https://git.kernel.org/stable/c/a61c6ae1dae2611082b831b4aaa780878099c012"
        }
      ],
      "title": "ceph: lock mutex in ceph_mds_check_access()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89990",
    "datePublished": "2026-09-16T10:33:04.371Z",
    "dateReserved": "2026-09-11T19:38:34.780Z",
    "dateUpdated": "2026-09-16T14:41:05.472Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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