Summary
Hugo: Symlink confinement bypass in resources.Get
Commit: f8b5fa09a6, Fix prevention of direct symlink reads in resources.Get
Affected versions: v0.123.0 through v0.161.1. Earlier versions are not affected.
Fixed in: v0.162.0.
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 resources.Get "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.
Mitigation. v0.162.0 calls LstatIfPossible and rejects symlinked entries with os.ErrNotExist, matching the behaviour of pre-v0.123.0 releases and of the directory-walking code paths.
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.
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Frequently Asked Questions
- What is CVE-2026-50135? CVE-2026-50135 is a medium-severity security vulnerability in github.com/gohugoio/hugo (go), affecting versions >= 0.123.0, < 0.162.0. It is fixed in 0.162.0.
- Which versions of github.com/gohugoio/hugo are affected by CVE-2026-50135? github.com/gohugoio/hugo (go) versions >= 0.123.0, < 0.162.0 is affected.
- Is there a fix for CVE-2026-50135? Yes. CVE-2026-50135 is fixed in 0.162.0. Upgrade to this version or later.
- Is CVE-2026-50135 exploitable, and should I be worried? Whether CVE-2026-50135 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 CVE-2026-50135 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 CVE-2026-50135? Upgrade
github.com/gohugoio/hugoto 0.162.0 or later.