GHSA-C3WQ-J5VH-68RC
Vulnerability from github – Published: 2026-06-19 17:45 – Updated: 2026-06-19 17:45Affected 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.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/gohugoio/hugo"
},
"ranges": [
{
"events": [
{
"introduced": "0.123.0"
},
{
"fixed": "0.163.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-19T17:45:38Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "**Affected versions:** v0.123.0 through v0.163.0. Earlier versions are not affected.\n**Fixed in:** v0.163.1.\n**Severity:** Medium. Requires the attacker to be able to place (or convince a site author to place) a symlink inside a mounted directory \u2014 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.\n\n**Description.** Hugo\u0027s 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\u0027s contents. This effectively let a symlink planted inside a theme or local mount read arbitrary files reachable to the user running `hugo`.",
"id": "GHSA-c3wq-j5vh-68rc",
"modified": "2026-06-19T17:45:38Z",
"published": "2026-06-19T17:45:38Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gohugoio/hugo/security/advisories/GHSA-c3wq-j5vh-68rc"
},
{
"type": "PACKAGE",
"url": "https://github.com/gohugoio/hugo"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "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",
"type": "CVSS_V4"
}
],
"summary": "Hugo: Symlink confinement bypass in os.ReadFile"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.