CVE-2026-89899 (GCVE-0-2026-89899)
Vulnerability from cvelistv5
Published
2026-09-16 10:31
Modified
2026-10-19 08:54
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: media: cec: disable delayed work before freeing an interrupted transmit cec_transmit_msg_fh() drops adap->lock to wait for a blocking transmit in wait_for_completion_killable(). If that wait is interrupted by a signal, cancel_delayed_work_sync() can run before the CEC kthread arms the reply timeout via schedule_delayed_work(&data->work) in cec_transmit_done_ts(). The work is then armed after the cancel, and the data is freed with its delayed_work still pending: ODEBUG: free active (active state 0) object: ... hint: cec_wait_timeout Use disable_delayed_work_sync(): it cancels the work and disables it, so the later schedule_delayed_work() becomes a no-op and the work cannot be re-armed. The data is freed right after, so it need not be re-enabled.
References
Impacted products
Vendor Product Version
Linux Linux Version: 490d84f6d73c12f4204241cff8651eed60aae914
Version: 490d84f6d73c12f4204241cff8651eed60aae914
Version: 490d84f6d73c12f4204241cff8651eed60aae914
Version: 490d84f6d73c12f4204241cff8651eed60aae914
Version: e448dfd6d3ec944411f6575bc24e4f8baa1e297f
Version: 2781b86d7e45de09befa5ace296b66787146561f
Version: 4.18.19   ≤
Version: 4.19.2   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/cec/core/cec-adap.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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            {
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            },
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              "status": "affected",
              "version": "4.18.19",
              "versionType": "semver"
            },
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              "status": "affected",
              "version": "4.19.2",
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/cec/core/cec-adap.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "lessThan": "4.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "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",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.18.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.19.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: cec: disable delayed work before freeing an interrupted transmit\n\ncec_transmit_msg_fh() drops adap-\u003elock to wait for a blocking transmit in\nwait_for_completion_killable(). If that wait is interrupted by a signal,\ncancel_delayed_work_sync() can run before the CEC kthread arms the reply\ntimeout via schedule_delayed_work(\u0026data-\u003ework) in cec_transmit_done_ts().\nThe work is then armed after the cancel, and the data is freed with its\ndelayed_work still pending:\n\n  ODEBUG: free active (active state 0) object: ... hint: cec_wait_timeout\n\nUse disable_delayed_work_sync(): it cancels the work and disables it, so\nthe later schedule_delayed_work() becomes a no-op and the work cannot be\nre-armed. The data is freed right after, so it need not be re-enabled."
        }
      ],
      "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 cec_transmit_msg_fh(), reached only via the local CEC_TRANSMIT ioctl on /dev/cec* (cec_ioctl to cec_transmit). A CEC peer on the HDMI bus cannot signal-interrupt wait_for_completion_killable(), so this is Local, unlike CEC RX IRQ bugs scored Adjacent.\nAC:L - The attacker issues a blocking CEC_TRANSMIT with a reply timeout and signals their own thread so cancel_delayed_work_sync() races the CEC kthread arming data-\u003ework in cec_transmit_done_ts(). They control both sides and can retry; syzkaller triggered it.\nPR:L - cec_open() defaults to CEC_MODE_INITIATOR, and neither CEC_TRANSMIT nor CEC_ADAP_S_LOG_ADDRS calls capable(). Only raw mode needs CAP_SYS_RAWIO and monitor modes need CAP_NET_ADMIN, neither required here. Unprivileged users with /dev/cec (video group, uaccess, Android HDMI-CEC) can trigger it.\nUI:N - The attacker opens /dev/cec, configures logical addresses, issues the blocking transmit ioctl, and delivers a signal to their own process. No separate victim action is required.\nS:U - The use-after-free corrupts kernel heap (struct cec_data) in the host kernel. It does not cross a VM, IOMMU, or other separate security authority.\nC:H - cec_wait_timeout() runs on a kmalloc\u0027d struct cec_data after kfree(), so a sprayed replacement object yields an attacker-controlled adap pointer and list walks. Per kernel CNA guidance, use-after-free is High confidentiality.\nI:H - The delayed-work UAF lets the attacker spray struct cec_data and corrupt list_heads and the adapter mutex when cec_wait_timeout()/cec_data_cancel() run, enabling arbitrary write and control-flow hijack. Per kernel CNA guidance, use-after-free is High integrity.\nA:H - Freeing struct cec_data while its delayed_work is still pending causes cec_wait_timeout() to run on freed memory, producing a kernel oops or panic even without a full exploit. Per kernel CNA guidance, use-after-free is High availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:54:32.139Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9a951931d4b4084acd64fa55fc3672a9da45ddf9"
        },
        {
          "url": "https://git.kernel.org/stable/c/a3adb63b121937b97f7fdc51e96564c7c799538b"
        },
        {
          "url": "https://git.kernel.org/stable/c/9c6ceb0949227c1f0cf0e19393daec72d9889871"
        },
        {
          "url": "https://git.kernel.org/stable/c/0fbd5c2327020858c45b2d1c65775d64cdeca523"
        }
      ],
      "title": "media: cec: disable delayed work before freeing an interrupted transmit",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89899",
    "datePublished": "2026-09-16T10:31:59.589Z",
    "dateReserved": "2026-09-11T19:38:34.774Z",
    "dateUpdated": "2026-10-19T08:54:32.139Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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