CVE-2026-89489

Status: ReceivedHigh (7.8)—

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

openrisc: fix arbitrary kernel memory access via or1k_atomic syscall

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly.

The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context.

Read full descriptionShow less

Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT.

[shorne@gmail.com: fix comment style]

Technical details traces, logs and code from the original report

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.18%
Percentile among all scored CVEs: 7
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.

ExploitationT1068 Exploitation for Privilege Escalationprivilege escalation95 %
Primary impactT1059 Command and Scripting Interpreterexecution90 %
Secondary impactT1005 Data from Local Systemcollection80 %
Secondary impactT1565.001 Stored Data Manipulationimpact85 %

Acceso local sin interacción (AV:L, PR:L, UI:N) permite leer/escribir memoria kernel arbitraria via syscall or1k_atomic sin validación, escalando a ejecución de código kernel al sobrescribir sys_call_table.

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

Execution Prevention Threat Intelligence Program Restrict Web-Based Content Restrict File and Directory Permissions Privileged Account Management Remote Data Storage

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-2026-89489",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "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": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "bf310718c6fa6adeee06d207a55489546d860e2c",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "497cba0b02e5555d99fe9ee1dc478af743ab7f7a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "1f2e92e499d863f81df1732af59b4a3559969193",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "574ae2ac2b314aa33498cd2c28add106cbe644f2",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "a520e8cac54fb403f3800125b606f55fcad42cb9",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "d64a75369cd0f2ee79afcc9d9ca34a3890989379",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "b53435c079c78f89f70a62dd5a322cca4e292b34",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "9d02a4283e9ce4e9ca11ff00615bdacdb0515a1a",
              "lessThan": "78004e9a87f240df03e2f73120d291763c32e0a7",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/openrisc/kernel/entry.S"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.1"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.1",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/openrisc/kernel/entry.S"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-11T20:19:30.683",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1f2e92e499d863f81df1732af59b4a3559969193",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/497cba0b02e5555d99fe9ee1dc478af743ab7f7a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/574ae2ac2b314aa33498cd2c28add106cbe644f2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/78004e9a87f240df03e2f73120d291763c32e0a7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a520e8cac54fb403f3800125b606f55fcad42cb9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b53435c079c78f89f70a62dd5a322cca4e292b34",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bf310718c6fa6adeee06d207a55489546d860e2c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d64a75369cd0f2ee79afcc9d9ca34a3890989379",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nopenrisc: fix arbitrary kernel memory access via or1k_atomic syscall\n\nsys_or1k_atomic() (syscall 244 in the \"or1k\" ABI) takes two user\npointers, v1 and v2, and swaps the words they point to in hand-written\nassembly.\n\n    l.lwz   r29,0(r4)\n    l.lwz   r27,0(r5)\n    l.sw    0(r4),r27\n    l.sw    0(r5),r29\n\nThe pointers are not checked with access_ok(). The four memory\naccesses also have no exception table entries.\n\nA caller passes a kernel address as either pointer, and the syscall\nreads from and writes to it directly.\n\nThis gives an unprivileged process a kernel read/write primitive. It\noverwrites kernel data such as the sys_call_table, gaining code\nexecution in kernel context.\n\nCheck both pointers before entering the critical section. Add fixups\nfor the four memory accesses so faults on valid but unmapped user\naddresses return -EFAULT.\n\n[shorne@gmail.com: fix comment style]"
    }
  ],
  "lastModified": "2026-09-14T13:19:05.790",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}