Summary
Hugo: Symlink confinement bypass in os.ReadFile
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 the user running hugo.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is GHSA-C3WQ-J5VH-68RC? GHSA-C3WQ-J5VH-68RC is a medium-severity security vulnerability in github.com/gohugoio/hugo (go), affecting versions >= 0.123.0, < 0.163.1. It is fixed in 0.163.1.
- Which versions of github.com/gohugoio/hugo are affected by GHSA-C3WQ-J5VH-68RC? github.com/gohugoio/hugo (go) versions >= 0.123.0, < 0.163.1 is affected.
- Is there a fix for GHSA-C3WQ-J5VH-68RC? Yes. GHSA-C3WQ-J5VH-68RC is fixed in 0.163.1. Upgrade to this version or later.
- Is GHSA-C3WQ-J5VH-68RC exploitable, and should I be worried? Whether GHSA-C3WQ-J5VH-68RC is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-C3WQ-J5VH-68RC is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-C3WQ-J5VH-68RC? Upgrade
github.com/gohugoio/hugoto 0.163.1 or later.