# CVE-2026-80427: bestzip before 2.2.6 and 3.0.x before 3.0.2 Argument Injection via Missing Option Delimiter

> Attackers can execute arbitrary commands by passing malicious filenames starting with hyphens to the bestzip library, which fails to separate options from file paths.

- **Severity:** High 8.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Aug 2026
- **Updated:** 29 Aug 2026
- **Also known as:** GHSA-p87m-9567-rgcc

## What is CVE-2026-80427?

CVE-2026-80427 is a high-severity command injection vulnerability in nfriedly bestzip, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

bestzip builds the argument list for the system zip utility without separating options from operands. The destination archive path and the caller-supplied source paths are passed to the child process with no -- delimiter between them, so any source entry beginning with a hyphen is interpreted by zip as an option rather than a file name. zip accepts -T to test the finished archive and -TT to name the command used to perform that test, so a source list containing those two entries and a command string causes zip to run that command through a shell once the archive has been written. An application that passes a file name or path it received from an untrusted source into the bestzip API therefore executes a command of the supplier's choosing. Versions 2.2.6 and 3.0.2 add the delimiter.

Weakness: CWE-88 (Improper Neutralization of Argument Delimiters in a Command)

## Which versions are affected by CVE-2026-80427?


## How do I fix CVE-2026-80427?

No fix has been published for CVE-2026-80427 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-80427 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-80427 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80427 and fix it if it is affected.

What it is: CVE-2026-80427 is a high-severity command injection vulnerability in nfriedly bestzip, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-80427 exists.

Affected product: nfriedly bestzip. 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-2026-80427/ (Markdown: https://insights.sbomify.com/CVE-2026-80427/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80427
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80427
- OSV: https://osv.dev/vulnerability/CVE-2026-80427

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80427/
Summaries are generated and may contain mistakes; the official description above is the record.