CVE-2026-89899: media: cec: disable delayed work before freeing an interrupted transmit
In the Linux kernel, the following vulnerability has been resolved:
media: cec: disable delayed work before freeing an interrupted transmit
cectransmitmsgfh() drops adap->lock to wait for a blocking transmit in waitforcompletionkillable(). If that wait is interrupted by a signal, canceldelayedworksync() can run before the CEC kthread arms the reply timeout via scheduledelayedwork(&data->work) in cectransmitdonets(). The work is then armed after the cancel, and the data is freed with its delayedwork still pending:
ODEBUG: free active (active state 0) object: ... hint: cecwaittimeout
Use disabledelayedworksync(): it cancels the work and disables it, so the later scheduledelayedwork() becomes a no-op and the work cannot be re-armed. The data is freed right after, so it need not be re-enabled.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In the Linux kernel media CEC transmit path, use disable_delayed_work_sync() instead of cancel_delayed_work_sync() before freeing an interrupted transmit, so a later schedule_delayed_work() becomes a no-op and the delayed work cannot be re-armed.
Event History
Frequently Asked Questions
What conditions are required to trigger the vulnerable path?
A blocking CEC transmit must be waiting in cec_transmit_msg_fh(), and that wait must be interrupted by a signal. A timing race is then required: the cancellation occurs before the CEC kernel thread arms the reply-timeout delayed work.
What is the consequence of winning the race?
The transmit data can be freed while its delayed_work remains pending. When that delayed work later runs, it can access freed data.
How is the issue corrected?
The fix uses disable_delayed_work_sync() rather than cancel_delayed_work_sync(). This both cancels the work and prevents the later schedule_delayed_work() call from re-arming it before the associated data is freed.