CVE-2026-80749: drm/connector/hdmi: Fix out of bounds memory read
In the Linux kernel, the following vulnerability has been resolved:
drm/connector/hdmi: Fix out of bounds memory read
A helper function was copying a given audio infoframe into the connector's copy but using the size of the destination (a generic target, sized to accept many different data blocks) not the source (a very specific type of data block). Thus, it was copying 60 bytes of data from a 28 byte allocation.
Fix that by using the source size instead, together with a build bug on the source size actually being smaller than the destination.
I hit this running KUnit tests under KASAN (while debugging something else entirely). In the real world, it seems unlikely to cause an actual problem. It is a read not a write so it can't corrupt any memory. However, it could potentially fall off the end of a page and cause an accvio bug.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
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 HDMI audio infoframe copy helper, use the source data size rather than the generic destination size, ensuring the copy does not read beyond the source allocation when the source is smaller than the destination.
Event History
Frequently Asked Questions
What conditions are needed to trigger the faulty read?
The affected helper must copy an HDMI audio infoframe into the connector’s generic data-block storage. The reported trigger occurred during KUnit testing with KASAN enabled; the data indicates that real-world impact is considered unlikely.
What is the practical impact if the out-of-bounds read occurs?
This is an out-of-bounds read, not a write, so it cannot corrupt memory through this flaw. It could read past the end of a page and trigger an access-violation bug.
How was the issue corrected?
The copy operation was changed to use the source audio-infoframe size rather than the larger destination size. A build-time check was also added to ensure the source remains smaller than the destination.