# CVE-2026-63910: dma-buf: fix UAF in dma_buf_fd() tracepoint

> A race condition in the Linux kernel's dma-buf tracepoint allows a use-after-free, potentially enabling local attackers to execute 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:** 19 Jul 2026
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-63910, GHSA-cwcv-9vv2-wx88, UBUNTU-CVE-2026-63910

## What is CVE-2026-63910?

CVE-2026-63910 is a high-severity use after free vulnerability in Linux, published on 19 Jul 2026. 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:

dma-buf: fix UAF in dma_buf_fd() tracepoint

Once FD_ADD() returns, the fd is live in the file descriptor table
and a thread sharing that table can close() it before DMA_BUF_TRACE()
runs. The close drops the last reference, __fput() frees the dma_buf,
and the tracepoint then dereferences dmabuf to take dmabuf->name_lock
-- slab-use-after-free.

Split FD_ADD() back into get_unused_fd_flags() + fd_install() and
emit the tracepoint between them. While the fdtable slot is reserved
with a NULL file pointer, a racing close() returns -EBADF without
entering __fput(), so the dma_buf stays alive across the trace. Same
approach as commit 2d76319c4cbb ("dma-buf: fix UAF in dma_buf_put()
tracepoint").

This undoes the FD_ADD() conversion done in commit 34dfce523c90
("dma: convert dma_buf_fd() to FD_ADD()"); FD_ADD() has no place to
hook the tracepoint safely.

## Which versions are affected by CVE-2026-63910?


## How do I fix CVE-2026-63910?

Apply the vendor's patch.

## Is CVE-2026-63910 being exploited?

There is no known exploitation of CVE-2026-63910 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63910 and fix it if it is affected.

What it is: CVE-2026-63910 is a high-severity use after free vulnerability in Linux, published on 19 Jul 2026. 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-2026-63910 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-2026-63910/ (Markdown: https://insights.sbomify.com/CVE-2026-63910/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63910
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63910
- OSV: https://osv.dev/vulnerability/CVE-2026-63910

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63910/
Summaries are generated and may contain mistakes; the official description above is the record.