# CVE-2026-90616: Path traversal in Flatpak

> A malicious sandboxed app can exploit missing symlink protection to access host files and execute arbitrary code on the host system.

- **Severity:** High 7.4 (`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** CLSA-2026-1789577977, CLSA-2026-1789979782, CLSA-2026-1790035964, DEBIAN-CVE-2026-90616, GHSA-8688-9x26-hhxj, GHSA-vhx5-8pfj-7wrv, OESA-2026-4098, UBUNTU-CVE-2026-90616

## What is CVE-2026-90616?

CVE-2026-90616 is a high-severity path traversal vulnerability in Flatpak, published on 12 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.

Weakness: CWE-61 (UNIX Symbolic Link (Symlink) Following)

## Which versions are affected by CVE-2026-90616?


## How do I fix CVE-2026-90616?

Upgrade to a fixed version.

## Is CVE-2026-90616 being exploited?

There is no known exploitation of CVE-2026-90616 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90616 and fix it if it is affected.

What it is: CVE-2026-90616 is a high-severity path traversal vulnerability in Flatpak, published on 12 Sep 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-2026-90616 in the wild and no public exploit code.

Affected product: Flatpak. 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-2026-90616/ (Markdown: https://insights.sbomify.com/CVE-2026-90616/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90616
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90616
- OSV: https://osv.dev/vulnerability/CVE-2026-90616

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90616/
Summaries are generated and may contain mistakes; the official description above is the record.