# CVE-2026-65609: Out-of-bounds write in nnn

> An attacker can execute arbitrary code or escalate privileges by tricking a user into loading a malicious session file in the nnn file manager.

- **Severity:** Low 2.4 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:N/VI:L/VA:L/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:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 20 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-65609, GHSA-r4wp-c597-23pf, UBUNTU-CVE-2026-65609

## What is CVE-2026-65609?

CVE-2026-65609 is a low-severity memory corruption vulnerability in nnn, published on 19 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

nnn is vulnerable to Out-of-Bound write vulnerability. Due to lack of validation of attacker-controlled length fields deserialized from a session file, a crafted session file can cause nnn to write data beyond the bounds of fixed-size global buffers when loaded with the -s option. An attacker who can place a malicious session file in the victim's nnn session directory can exploit this to corrupt adjacent global state.

Maintainer of this project was notified about this vulnerability. It might has been addressed, but the maintainer did not provide a vulnerable version range. Only version 5.2 was tested and confirmed as vulnerable.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-65609?


## How do I fix CVE-2026-65609?

No fix has been published for CVE-2026-65609 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-65609 being exploited?

There is no known exploitation of CVE-2026-65609 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-65609 and fix it if it is affected.

What it is: CVE-2026-65609 is a low-severity memory corruption vulnerability in nnn, published on 19 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-65609 in the wild and no public exploit code.

Affected product: nnn. 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-2026-65609/ (Markdown: https://insights.sbomify.com/CVE-2026-65609/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65609
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65609
- OSV: https://osv.dev/vulnerability/CVE-2026-65609

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-65609/
Summaries are generated and may contain mistakes; the official description above is the record.