# 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.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 1 Oct 2025
- **Updated:** 23 May 2026
- **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, ROOT-OS-UBUNTU-2204-CVE-2025-39923, ROOT-OS-UBUNTU-2404-CVE-2025-39923, UBUNTU-CVE-2025-39923

## 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/CY01EKQVWE36.B9X5TDXAREPF@fairphone.com/
[2]: https://lore.kernel.org/r/20230626145959.646747-1-krzysztof.kozlowski@linaro.org/

## Which versions are affected by CVE-2025-39923?

It affects 2 products.


Products: 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.

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## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39923 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-39923 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-39923/ (Markdown: https://insights.sbomify.com/CVE-2025-39923/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39923
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39923
- OSV: https://osv.dev/vulnerability/CVE-2025-39923

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39923/
Summaries are generated and may contain mistakes; the official description above is the record.