# CVE-2025-39978: octeontx2-pf: Fix potential use after free in otx2_tc_add_flow()

> A use-after-free vulnerability in the Linux kernel's octeontx2-pf driver allows attackers to potentially execute arbitrary code or escalate privileges.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 15 Oct 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-39978, DEBIAN-CVE-2025-39978, GHSA-2829-fqm4-jgr9, ROOT-OS-DEBIAN-12-CVE-2025-39978, ROOT-OS-DEBIAN-13-CVE-2025-39978, ROOT-OS-UBUNTU-2204-CVE-2025-39978, ROOT-OS-UBUNTU-2404-CVE-2025-39978, UBUNTU-CVE-2025-39978

## What is CVE-2025-39978?

CVE-2025-39978 is a high-severity use after free vulnerability in Linux, published on 15 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:

octeontx2-pf: Fix potential use after free in otx2_tc_add_flow()

This code calls kfree_rcu(new_node, rcu) and then dereferences "new_node"
and then dereferences it on the next line.  Two lines later, we take
a mutex so I don't think this is an RCU safe region.  Re-order it to do
the dereferences before queuing up the free.

## Which versions are affected by CVE-2025-39978?


## How do I fix CVE-2025-39978?

Apply the vendor's patch.

## Is CVE-2025-39978 being exploited?

There is no known exploitation of CVE-2025-39978 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39978 and fix it if it is affected.

What it is: CVE-2025-39978 is a high-severity use after free vulnerability in Linux, published on 15 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-2025-39978 in the wild and no public exploit code.

Affected product: 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-2025-39978/ (Markdown: https://insights.sbomify.com/CVE-2025-39978/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39978
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39978
- OSV: https://osv.dev/vulnerability/CVE-2025-39978

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39978/
Summaries are generated and may contain mistakes; the official description above is the record.