{"id":"CVE-2026-89899","state":"PUBLISHED","title":"media: cec: disable delayed work before freeing an interrupted transmit","description":"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->lock 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(&data->work) 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.","publishedAt":"2026-09-16T10:31:59.589Z","updatedAt":"2026-10-19T08:54:32.139Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"9a951931d4b4084acd64fa55fc3672a9da45ddf9","versionType":"git"},{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"a3adb63b121937b97f7fdc51e96564c7c799538b","versionType":"git"},{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"9c6ceb0949227c1f0cf0e19393daec72d9889871","versionType":"git"},{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"0fbd5c2327020858c45b2d1c65775d64cdeca523","versionType":"git"},{"version":"e448dfd6d3ec944411f6575bc24e4f8baa1e297f","status":"affected","versionType":"git"},{"version":"2781b86d7e45de09befa5ace296b66787146561f","status":"affected","versionType":"git"},{"version":"4.18.19","status":"affected","lessThan":"4.19","versionType":"semver"},{"version":"4.19.2","status":"affected","lessThan":"4.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/cec/core/cec-adap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.20","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.20","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.51","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/cec/core/cec-adap.c"]}],"references":["https://git.kernel.org/stable/c/9a951931d4b4084acd64fa55fc3672a9da45ddf9","https://git.kernel.org/stable/c/a3adb63b121937b97f7fdc51e96564c7c799538b","https://git.kernel.org/stable/c/9c6ceb0949227c1f0cf0e19393daec72d9889871","https://git.kernel.org/stable/c/0fbd5c2327020858c45b2d1c65775d64cdeca523"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/89xxx/CVE-2026-89899.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-89899","state":"PUBLISHED","datePublished":"2026-09-16T10:31:59.589Z","dateUpdated":"2026-10-19T08:54:32.139Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.774Z"},"containers":{"cna":{"title":"media: cec: disable delayed work before freeing an interrupted transmit","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->lock 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(&data->work) 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"9a951931d4b4084acd64fa55fc3672a9da45ddf9","versionType":"git"},{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"a3adb63b121937b97f7fdc51e96564c7c799538b","versionType":"git"},{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"9c6ceb0949227c1f0cf0e19393daec72d9889871","versionType":"git"},{"version":"490d84f6d73c12f4204241cff8651eed60aae914","status":"affected","lessThan":"0fbd5c2327020858c45b2d1c65775d64cdeca523","versionType":"git"},{"version":"e448dfd6d3ec944411f6575bc24e4f8baa1e297f","status":"affected","versionType":"git"},{"version":"2781b86d7e45de09befa5ace296b66787146561f","status":"affected","versionType":"git"},{"version":"4.18.19","status":"affected","lessThan":"4.19","versionType":"semver"},{"version":"4.19.2","status":"affected","lessThan":"4.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/cec/core/cec-adap.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.20","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.20","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.51","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.5","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/cec/core/cec-adap.c"]}],"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"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"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->work 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'd 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":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:54:32.139Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"6.18.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"7.2.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.20","versionEndExcluding":"7.3"},{"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}