Hugo: Symlink confinement bypass in os.ReadFile

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.0 · CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Affected versions: v0.123.0 through v0.163.0. Earlier versions are not affected. Fixed in: v0.163.1. Severity: Medium. Requires the attacker to be able to place (or convince a site author to place) a symlink inside a mounted directory — for example, inside a locally-vendored theme under themes/. Themes mounted as Go modules from GitHub have symlinks stripped on download and are not affected. Multi-directory walks (e.g. content/asset walking) were not affected either; only direct lookups via resources.Get followed symlinks. Description. Hugo's virtual filesystem is designed so that files under a mount cannot reach outside the mount tree. A regression introduced in v0.123.0 caused RootMappingFs.statRoot to call Stat (which follows symlinks) instead of Lstat, so a direct os.ReadFile "somefile" where somefile was a symlink pointing outside the mount would return the target's contents. This effectively let a symlink planted inside a theme or local mount read arbitrary files reachable to…

Published by the source

19 Jun 2026, 17:45 UTC

Last modified by the source

19 Jun 2026, 17:45 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c3wq-j5vh-68rc

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# Patch Next advisory brief: GHSA-c3wq-j5vh-68rc

Advisory: Hugo: Symlink confinement bypass in os.ReadFile
IDs: GHSA-c3wq-j5vh-68rc
Record: https://patchnext.com/advisories/ghsa-c3wq-j5vh-68rc (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/gohugoio/hugo 0.163.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gohugoio/hugo: affected >= 0.123.0, < 0.163.1; fixed in 0.163.1

## Suggested inspection (read-only)
- Go github.com/gohugoio/hugo: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/gohugoio/hugo.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-c3wq-j5vh-68rc (GitHub-reviewed advisory GHSA-c3wq-j5vh-68rc lists affected ranges: Go github.com/gohugoio/hugo >=0.123.0 <0.163.1)

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