# CVE-2026-58403: Hugo symlink confinement bypass in os.ReadFile

> A symlink confinement bypass in Hugo allows attackers to read arbitrary files outside the mount tree via crafted symlinks in themes or local mounts.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Jul 2026
- **Updated:** 6 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-58403, GHSA-c3wq-j5vh-68rc, GO-2026-5309, UBUNTU-CVE-2026-58403

## What is CVE-2026-58403?

CVE-2026-58403 is a medium-severity path traversal vulnerability in gohugoio hugo, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Hugo is a static site generator. From v0.123.0 through v0.163.0, Hugo's virtual filesystem is designed so that files under a mount cannot reach outside the mount tree, but a regression 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. This issue is fixed in v0.163.1.

Weakness: CWE-59 (Improper Link Resolution Before File Access)

## Which versions are affected by CVE-2026-58403?

3 open source packages ship an affected version, including github.com/gohugoio/hugo. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/gohugoio/hugo` | Go | From 0.123.0 | 0.163.1 |
| `github.com/gohugoio/hugo` | Go | From 0.123.0 | 0.163.1 |
| `github.com/gohugoio/hugo` | Go | From 0.123.0 | 0.163.1 |

Products: Gohugo Hugo.

## How do I fix CVE-2026-58403?

Upgrade github.com/gohugoio/hugo to 0.163.1 or later.

## Is CVE-2026-58403 being exploited?

There is no known exploitation of CVE-2026-58403 in the wild and no public exploit code.

## Other vulnerabilities in gohugoio hugo

- [CVE-2026-75926](https://insights.sbomify.com/CVE-2026-75926/): Hugo 0.162.0 to 0.164.x - Node Permission Model Bypass via Default TailwindCSS Child-Process Grant (critical 9.3)
- [CVE-2026-100690](https://insights.sbomify.com/CVE-2026-100690/): Hugo v0.161.0 to v0.165.0 Arbitrary File Read via Symlinks (high 8.7)
- [CVE-2026-100692](https://insights.sbomify.com/CVE-2026-100692/): Hugo before v0.166.0 Path Traversal via Symlinked Mount Roots (high 8.7)
- [CVE-2026-100693](https://insights.sbomify.com/CVE-2026-100693/): Hugo v0.162.0 before v0.166.0 IP-literal Deny Rule Bypass (high 8.6)
- [CVE-2020-26284](https://insights.sbomify.com/CVE-2020-26284/): Hugo can execute a binary from the current directory on Windows (high 7.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-58403 and fix it if it is affected.

What it is: CVE-2026-58403 is a medium-severity path traversal vulnerability in gohugoio hugo, published on 6 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-58403 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/gohugoio/hugo (Go): affected from 0.123.0; fixed in 0.163.1
- github.com/gohugoio/hugo (Go): affected from 0.123.0; fixed in 0.163.1
- github.com/gohugoio/hugo (Go): affected from 0.123.0; fixed in 0.163.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-58403/ (Markdown: https://insights.sbomify.com/CVE-2026-58403/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58403
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58403
- OSV: https://osv.dev/vulnerability/CVE-2026-58403

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58403/
Summaries are generated and may contain mistakes; the official description above is the record.