CVE-2026-58404
Hugo security.http.urls deny rules bypassed by alternate IPv4 encodings
Description
Hugo is a static site generator. From v0.162.0 through v0.163.0, the default security.http.urls policy denies requests to loopback, internal, and cloud-metadata IPv4 literals, but the deny rule only matched dotted-decimal notation, so alternate IPv4 encodings of the same addresses, including integer, hex, or octal, passed the policy. 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 or CI builds; the same check is reused on redirects, so the gap also applies to each redirect hop. This issue is fixed in v0.163.1.
INFO
Published Date :
July 6, 2026, 8:16 p.m.
Last Modified :
July 6, 2026, 8:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-58404
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Hugo to v0.163.1 or later.
- Review and validate external URL inputs.
- Apply network segmentation for sensitive services.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-58404.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-58404 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-58404
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-58404 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-58404 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jul. 06, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'gohugoio', 'product': 'hugo', 'versions': [{'status': 'affected', 'version': '>= v0.162.0, < v0.163.1'}]}] Added Description Hugo is a static site generator. From v0.162.0 through v0.163.0, the default security.http.urls policy denies requests to loopback, internal, and cloud-metadata IPv4 literals, but the deny rule only matched dotted-decimal notation, so alternate IPv4 encodings of the same addresses, including integer, hex, or octal, passed the policy. 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 or CI builds; the same check is reused on redirects, so the gap also applies to each redirect hop. This issue is fixed in v0.163.1. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-918 Added Reference https://github.com/gohugoio/hugo/commit/a00b5c72ac57afe26df6688ece3ca544a56df372 Added Reference https://github.com/gohugoio/hugo/pull/15020 Added Reference https://github.com/gohugoio/hugo/releases/tag/v0.163.1 Added Reference https://github.com/gohugoio/hugo/security/advisories/GHSA-r46f-3rpw-hxrv