# CVE-2026-74426: afs: fix NULL pointer dereference in afs_get_tree()

> A local attacker can trigger a kernel crash via a null pointer dereference in the AFS filesystem mount path, causing denial of service.

- **Severity:** Not scored
- **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 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74426, DEBIAN-CVE-2026-74426, GHSA-8xv3-wjfw-qm6v, UBUNTU-CVE-2026-74426

## What is CVE-2026-74426?

CVE-2026-74426 is a vulnerability in Linux, published on 15 Aug 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:

afs: fix NULL pointer dereference in afs_get_tree()

afs_alloc_sbi() uses kzalloc for memory allocation. And, if
ctx->dyn_root is not null, as->cell and as->volume are null.
In trace_afs_get_tree() they are dereferenced.

KASAN error message:

KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 2 PID: 18478 Comm: syz-executor.7 Not tainted 5.10.246-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1
04/01/2014
RIP: 0010:perf_trace_afs_get_tree+0x1d9/0x550
include/trace/events/afs.h:1365

Call Trace:
trace_afs_get_tree include/trace/events/afs.h:1365 [inline]
afs_get_tree+0x922/0x1350 fs/afs/super.c:599
vfs_get_tree+0x8e/0x300 fs/super.c:1572
do_new_mount fs/namespace.c:3011 [inline]
path_mount+0x14a5/0x2220 fs/namespace.c:3341
do_mount fs/namespace.c:3354 [inline]
__do_sys_mount fs/namespace.c:3562 [inline]
__se_sys_mount fs/namespace.c:3539 [inline]
__x64_sys_mount+0x283/0x300 fs/namespace.c:3539
 do_syscall_64+0x33/0x50 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x67/0xd1

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

## Which versions are affected by CVE-2026-74426?


## How do I fix CVE-2026-74426?

Apply the vendor's patch.

## Is CVE-2026-74426 being exploited?

There is no known exploitation of CVE-2026-74426 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74426 and fix it if it is affected.

What it is: CVE-2026-74426 is a vulnerability in Linux, published on 15 Aug 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-2026-74426 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-2026-74426/ (Markdown: https://insights.sbomify.com/CVE-2026-74426/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74426
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74426
- OSV: https://osv.dev/vulnerability/CVE-2026-74426

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74426/
Summaries are generated and may contain mistakes; the official description above is the record.