# CVE-2026-54370: acl < 2.4.0 TOCTOU Symlink Traversal via getfacl/setfacl/chacl

> Local attackers can escalate privileges by exploiting a race condition in ACL utilities to redirect file operations to arbitrary files.

- **Severity:** High 7.2 (`CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA: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:** 29 Jun 2026
- **Updated:** 14 Jul 2026
- **Also known as:** AZL-91394, DEBIAN-CVE-2026-54370, ECHO-ae30-49be-9cc5, GHSA-r45p-762r-6pqj, ROOT-OS-DEBIAN-11-CVE-2026-54370, ROOT-OS-DEBIAN-12-CVE-2026-54370, ROOT-OS-DEBIAN-13-CVE-2026-54370, UBUNTU-CVE-2026-54370

## What is CVE-2026-54370?

CVE-2026-54370 is a high-severity vulnerability in acl, published on 29 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

acl before version 2.4.0 contains a time-of-check to time-of-use (TOCTOU) race condition vulnerability that allows local attackers to escalate privileges by replacing a pathname component with a symbolic link between an lstat() check and subsequent symlink-following operations such as stat(), chown(), chmod(), acl_get_file(), and acl_set_file(). Attackers who control a pathname component can redirect file access control list operations to arbitrary files when getfacl, setfacl, or chacl is invoked by a privileged process over an attacker-controlled path, resulting in local privilege escalation.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-54370?


## How do I fix CVE-2026-54370?

Upgrade to a fixed version.

## Is CVE-2026-54370 being exploited?

There is no known exploitation of CVE-2026-54370 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54370 and fix it if it is affected.

What it is: CVE-2026-54370 is a high-severity vulnerability in acl, published on 29 Jun 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-2026-54370 in the wild and no public exploit code.

Affected product: acl. 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-2026-54370/ (Markdown: https://insights.sbomify.com/CVE-2026-54370/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54370
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54370
- OSV: https://osv.dev/vulnerability/CVE-2026-54370

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54370/
Summaries are generated and may contain mistakes; the official description above is the record.