CVE-2026-89990

Status: ReceivedCritical (9.8)—

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:

Technical details traces, logs and code from the original report

  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

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Base score: 9.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.65%
Percentile among all scored CVEs: 49
Score date: 10/4/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access85 %
Primary impactT1499.004 Application or System Exploitationimpact90 %

Vulnerabilidad de use-after-free en el kernel Linux (AV:N/AC:L/PR:N) explotable remotamente. La condición de carrera causa pánico/DoS del kernel y potencial lectura de memoria antes de crash.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux Kernel^AI

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-89990",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "lessThan": "729c1ff670ece6f3d4b1738365a0b2f90d487523",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "lessThan": "ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "lessThan": "df1a97d5313fccadb08390306d49b194fb027392",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "596afb0b8933ba6ed7227adcc538db26feb25c74",
              "lessThan": "a61c6ae1dae2611082b831b4aaa780878099c012",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/ceph/mds_client.c",
            "fs/ceph/mds_client.h"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.10",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/ceph/mds_client.c",
            "fs/ceph/mds_client.h"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-16T11:17:10.133",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/729c1ff670ece6f3d4b1738365a0b2f90d487523",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a61c6ae1dae2611082b831b4aaa780878099c012",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/df1a97d5313fccadb08390306d49b194fb027392",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "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->s_cap_auths under\nmdsc->mutex, 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"
    }
  ],
  "lastModified": "2026-09-16T15:18:22.800",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}