# CVE-2026-74364: bpf: Reject exclusive maps as inner maps in map-in-map

> Attackers can bypass BPF map exclusivity checks by nesting exclusive maps in outer maps, allowing unauthorized modification of protected data.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **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-2026-74364, DEBIAN-CVE-2026-74364, GHSA-723q-c22r-gxfr, UBUNTU-CVE-2026-74364

## What is CVE-2026-74364?

CVE-2026-74364 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: Reject exclusive maps as inner maps in map-in-map

An exclusive map (created with excl_prog_hash) is bound to a single
program by hash: check_map_prog_compatibility() refuses to load any
program whose digest does not match map->excl_prog_sha. That check
only runs for maps a program references directly, i.e. its used_maps.
A map reached at runtime through a map-of-maps is never in used_maps,
and bpf_map_meta_equal() does not consider excl_prog_sha, so an
exclusive map can be inserted into a non-exclusive outer map and
then looked up and mutated by an unrelated program, bypassing the
exclusivity guarantee.

For the signed loader this defeats the metadata map exclusivity check
added in the signed loader: the cached map->sha[] is validated against
the signed hash while another program on a hostile host rewrites the
frozen map's contents through the outer map.

## Which versions are affected by CVE-2026-74364?


## How do I fix CVE-2026-74364?

Apply the vendor's patch.

## Is CVE-2026-74364 being exploited?

There is no known exploitation of CVE-2026-74364 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74364 and fix it if it is affected.

What it is: CVE-2026-74364 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-2026-74364 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-2026-74364/ (Markdown: https://insights.sbomify.com/CVE-2026-74364/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74364
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74364
- OSV: https://osv.dev/vulnerability/CVE-2026-74364

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74364/
Summaries are generated and may contain mistakes; the official description above is the record.