CVE-2025-39923 dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees
Missing error handling in the Qualcomm BAM DMA driver causes early boot crashes when required device tree properties are missing.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39923?
CVE-2025-39923 is a medium-severity vulnerability in Debian Debian Linux, published on 1 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: qcom: bam_dma: Fix DT error handling for num-channels/ees
When we don't have a clock specified in the device tree, we have no way to ensure the BAM is on. This is often the case for remotely-controlled or remotely-powered BAM instances. In this case, we need to read num-channels from the DT to have all the necessary information to complete probing.
However, at the moment invalid device trees without clock and without num-channels still continue probing, because the error handling is missing return statements. The driver will then later try to read the number of channels from the registers. This is unsafe, because it relies on boot firmware and lucky timing to succeed. Unfortunately, the lack of proper error handling here has been abused for several Qualcomm SoCs upstream, causing early boot crashes in several situations [1, 2].
Avoid these early crashes by erroring out when any of the required DT properties are missing. Note that this will break some of the existing DTs upstream (mainly BAM instances related to the crypto engine). However, clearly these DTs have never been tested properly, since the error in the kernel log was just ignored. It's safer to disable the crypto engine for these broken DTBs.
[1]: https://lore.kernel.org/r/[email protected]/ [2]: https://lore.kernel.org/r/[email protected]/
Which versions are affected by CVE-2025-39923?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39923?
Apply the vendor's patch.
Is CVE-2025-39923 being exploited?
There is no known exploitation of CVE-2025-39923 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-68025, AZL-74850, BELL-CVE-2025-39923, DEBIAN-CVE-2025-39923, GHSA-3gm7-2gq6-fqjf, ROOT-OS-DEBIAN-11-CVE-2025-39923 and 3 more.