CVE-2026-90291 (GCVE-0-2026-90291)
Vulnerability from cvelistv5
Published
2026-09-17 16:08
Modified
2026-10-21 12:50
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: module/dups: Fix use-after-free in kmod_dup_req lifetime handling The kmod dups code uses RCU to ensure that a kmod_dup_req instance is freed only after it is no longer referenced. When releasing an instance, the kmod_dup_request_delete() function removes the kmod_dup_req from the dup_kmod_reqs list, waits via synchronize_rcu() and finally frees it. However, this doesn't work correctly because parallel users referencing the instance in kmod_dup_request_exists_wait() don't enter an RCU read-side critical section. This can result in a use-after-free. The kmod_dup_request_exists_wait() function may need to hold a valid reference to a kmod_dup_req instance across a blocking wait until the corresponding modprobe command completes. This makes it unsuitable for RCU. Fix the issue by changing the lifecycle management of kmod_dup_req to use reference counting.
References
Impacted products
Vendor Product Version
Linux Linux Version: 8660484ed1cf3261e89e0bad94c6395597e87599
Version: 8660484ed1cf3261e89e0bad94c6395597e87599
Version: 8660484ed1cf3261e89e0bad94c6395597e87599
Version: 8660484ed1cf3261e89e0bad94c6395597e87599
Version: 8660484ed1cf3261e89e0bad94c6395597e87599
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/module/dups.c"
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "6.4"
            },
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              "version": "0",
              "versionType": "semver"
            },
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              "version": "6.12.110",
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            },
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              "version": "6.18.52",
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              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.12.110",
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                  "vulnerable": true
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                  "versionEndExcluding": "6.18.52",
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              ],
              "negate": false,
              "operator": "OR"
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          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmodule/dups: Fix use-after-free in kmod_dup_req lifetime handling\n\nThe kmod dups code uses RCU to ensure that a kmod_dup_req instance is freed\nonly after it is no longer referenced. When releasing an instance, the\nkmod_dup_request_delete() function removes the kmod_dup_req from the\ndup_kmod_reqs list, waits via synchronize_rcu() and finally frees it.\nHowever, this doesn\u0027t work correctly because parallel users referencing the\ninstance in kmod_dup_request_exists_wait() don\u0027t enter an RCU read-side\ncritical section. This can result in a use-after-free.\n\nThe kmod_dup_request_exists_wait() function may need to hold a valid\nreference to a kmod_dup_req instance across a blocking wait until the\ncorresponding modprobe command completes. This makes it unsuitable for RCU.\n\nFix the issue by changing the lifecycle management of kmod_dup_req to use\nreference counting."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is in kmod_dup_request_exists_wait(), reached from __request_module() when tracking a duplicate autoload. An unprivileged process hits that via socket(2) \u2192 __sys_socket() \u2192 __sock_create(), which calls request_module(\"net-pf-%d\") for an unloaded protocol family; the trigger is that local syscall, not a remote protocol message.\nAC:L - The attacker drives both sides: one socket() call\u0027s request_module() inserts a kmod_dup_req and kmod_dup_request_announce() queues kmod_dup_request_delete() for 60*HZ, then further socket() calls look up that entry, drop kmod_dup_mutex, and wait_for_completion_state() on first_req_done without rcu_read_lock, racing the delayed kfree.\nPR:L - __request_module() has no capable() check; it only calls security_kernel_module_request(), whose default LSM hook returns 0. __sock_create()\u0027s request_module(\"net-pf-%d\") path has no capability gate either, so a normal unprivileged local user can trigger the duplicate-autoload race.\nUI:N - The attacker issues their own socket() syscalls to force concurrent request_module() calls for the same net-pf-%d name; no other user must mount a filesystem, open a file, or otherwise cooperate.\nS:U - The use-after-free is of a kmalloc\u0027d kmod_dup_req in kernel/module/dups.c and corrupts host kernel heap. That is a standard in-kernel privilege-escalation impact inside one security authority, not a VM or IOMMU boundary crossing.\nC:H - After kmod_dup_request_delete() kfree()s the kmod_dup_req, a racing kmod_dup_request_exists_wait() still reads kmod_req-\u003edup_ret and takes first_req_done.wait.lock inside wait_for_common(). Reclaiming that slab lets the attacker control those contents, a UAF read primitive.\nI:H - wait_for_common() takes first_req_done.wait.lock and can __prepare_to_swait() onto the completion wait queue in the already-freed kmod_dup_req. Heap spraying that object yields an attacker-controlled wait-queue/list write, a UAF write and control-flow hijack primitive.\nA:H - Using a freed kmod_dup_req\u0027s completion spinlock in wait_for_common(), or kfree() racing wait_for_completion_state(\u0026kmod_req-\u003efirst_req_done), oopses or panics the kernel even without a full exploit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:50:49.946Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a3205bd1f218053575589b14caf8df667f344134"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c85e0fb528e039aa8ea1e9c2a1f64347f990541"
        },
        {
          "url": "https://git.kernel.org/stable/c/b2709aad7599f6fd957939b60f4a8323c8f08072"
        },
        {
          "url": "https://git.kernel.org/stable/c/cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca"
        },
        {
          "url": "https://git.kernel.org/stable/c/5eecb11b543f9f417bcf0dea239ff99c6af65dbd"
        }
      ],
      "title": "module/dups: Fix use-after-free in kmod_dup_req lifetime handling",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90291",
    "datePublished": "2026-09-17T16:08:18.700Z",
    "dateReserved": "2026-09-11T19:38:34.798Z",
    "dateUpdated": "2026-10-21T12:50:49.946Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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