# CVE-2026-88839: Busybox: busybox: passwd/group parser writes heap pointers out of bounds due to stale tokenize() endpoint

> An out-of-bounds write in BusyBox's passwd/group parser allows attackers to corrupt memory, potentially leading to code execution or privilege escalation.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** AZL-105125, DEBIAN-CVE-2026-88839, ECHO-2dbb-f14e-a8c4, GHSA-fr4j-cp66-9wc4, UBUNTU-CVE-2026-88839

## What is CVE-2026-88839?

CVE-2026-88839 is a medium-severity memory corruption vulnerability in Red Hat Hardened Images, published on 23 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

BusyBox passwd/group tokenize() references a stale endpoint pointer after trimming, causing an out-of-bounds write of heap pointers.

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

## Which versions are affected by CVE-2026-88839?


## How do I fix CVE-2026-88839?

Apply the vendor's patch.

## Is CVE-2026-88839 being exploited?

There is no known exploitation of CVE-2026-88839 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-88839 and fix it if it is affected.

What it is: CVE-2026-88839 is a medium-severity memory corruption vulnerability in Red Hat Hardened Images, published on 23 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-2026-88839 in the wild and no public exploit code.

Affected product: Red Hat Hardened Images. 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-2026-88839/ (Markdown: https://insights.sbomify.com/CVE-2026-88839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-88839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-88839
- OSV: https://osv.dev/vulnerability/CVE-2026-88839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-88839/
Summaries are generated and may contain mistakes; the official description above is the record.