How severe is CVE-2026-58404?

No CVSS score has been assigned to CVE-2026-58404 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-58404?

CVE-2026-58404 affects the following packages: github.com/gohugoio/hugo (Go). Ecosystems affected: Go.

How do I fix CVE-2026-58404?

Update github.com/gohugoio/hugo to 0.163.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-58404 is resolved across your whole dependency graph.

How do I detect CVE-2026-58404 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gohugoio/hugo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-58404 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-58404 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-58404 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-58404?

CVE-2026-58404 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-58404?

CVE-2026-58404 is classified as Server-Side Request Forgery (SSRF) (CWE-918). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-58404 published, and has it been updated?

CVE-2026-58404 was published on July 6, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-58404 — hugo

Fix: gohugoio/hugo@a00b5c7

CVE-2026-58404 is a Server-Side Request Forgery (SSRF) vulnerability in github.com/gohugoio/hugo. A fix is available for github.com/gohugoio/hugo — see the affected versions and patch details below.

Hugo security.http.urls deny rules bypassed by alternate IPv4 encodings

Also known asGHSA-r46f-3rpw-hxrvGO-2026-5606

Published

Jul 6, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-58404.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs31th percentile — riskier than 31% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/gohugoio/hugo

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The default security.http.urls policy denies requests to loopback, internal, and cloud-metadata IPv4 literals (e.g. http://127.0.0.1/, http://169.254.169.254/). The deny rule only matched dotted-decimal notation, so alternate IPv4 encodings of the same addresses — integer, hex, or octal, which contain no dot — passed the policy:

http://2130706433/ → 127.0.0.1
http://2852039166/ → 169.254.169.254 (cloud metadata)
http://0x7f000001/, http://017700000001/, http://0/

When a template passes an untrusted or data-derived URL to resources.GetRemote and the host platform uses the cgo system resolver, these encodings resolve to the blocked address — allowing build-time server-side requests to loopback and internal services, including the cloud-metadata endpoint in hosted/CI builds. The same check is reused on redirects, so the gap also applies to each redirect hop.

This affects sites that rely on security.http.urls as a security boundary while fetching attacker-influenced remote URLs; it does not affect sites that fully trust the URLs they fetch.

Patches

Fixed in v0.163.1. Integer/hex/octal IPv4 hosts are now canonicalized to dotted-decimal before the policy is applied, so every encoding of an address is treated alike. No configuration change is required.

Workarounds

Avoid passing untrusted URLs to resources.GetRemote, or tighten security.http.urls to an explicit allow-list of trusted hosts.

Affected versions

v0.162.0 – v0.163.0 (patched in v0.163.1).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/gohugoio/hugo`	≥ 0.162.0&&< 0.163.1	0.163.1`go get github.com/gohugoio/hugo@v0.163.1`

Affected Products

1 product · 1 configurations

Application

hugogohugo

≥ 0.162.0 && < 0.163.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gohugoio/hugo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/gohugoio/hugo to 0.163.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-58404 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
Red Hat Hardened Images	`hugo-main-0.163.3-0.1.hum1`	RHSA-2026:36862

Frequently Asked Questions

### Impact The default `security.http.urls` policy denies requests to loopback, internal, and cloud-metadata IPv4 literals (e.g. `http://127.0.0.1/`, `http://169.254.169.254/`). The deny rule only matched dotted-decimal notation, so alternate IPv4 encodings of the same addresses — integer, hex, or octal, which contain no dot — passed the policy: - `http://2130706433/` → `127.0.0.1` - `http://2852039166/` → `169.254.169.254` (cloud metadata) - `http://0x7f000001/`, `http://017700000001/`, `http://0/` When a template passes an untrusted or data-derived URL to `resources.Ge

O3 Security · Impact-Aware SCA

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