# CVE-2026-74354: bpf: Take mmap_lock in zap_pages()

> A race condition in the Linux kernel BPF subsystem allows attackers to cause denial of service or potentially escalate privileges via improper locking in zap_pages().

- **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 Aug 2026
- **Updated:** 16 Oct 2026
- **Also known as:** BELL-CVE-2026-74354, DEBIAN-CVE-2026-74354, GHSA-g336-8h5f-6m63, UBUNTU-CVE-2026-74354

## What is CVE-2026-74354?

CVE-2026-74354 is a high-severity 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:

bpf: Take mmap_lock in zap_pages()

zap_vma_range() requires the owning mm's mmap_lock to be held.

Taking mmap_read_lock under arena->lock would AB-BA against
arena_vm_close() and arena_map_mmap(), both of which run with
mmap_write_lock held and then acquire arena->lock. Instead drop
arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and
re-resolve the vma via find_vma() since it may have been unmapped or
replaced while waiting.

Track processed vmls with a per-call generation in vml->zap_gen and
serialize zap_pages() callers with a new arena->zap_mutex so
concurrent callers on different uaddr ranges do not mark each other's
vmls processed before the zap is done.

## Which versions are affected by CVE-2026-74354?


## How do I fix CVE-2026-74354?

Apply the vendor's patch.

## Is CVE-2026-74354 being exploited?

There is no known exploitation of CVE-2026-74354 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74354 and fix it if it is affected.

What it is: CVE-2026-74354 is a high-severity 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-2026-74354 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-2026-74354/ (Markdown: https://insights.sbomify.com/CVE-2026-74354/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74354
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74354
- OSV: https://osv.dev/vulnerability/CVE-2026-74354

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74354/
Summaries are generated and may contain mistakes; the official description above is the record.