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Fencer Vulns
medium 5.4

CVE-2026-58402 json

Hugo default code block renderer XSS via unescaped code-fence language

published 2026-06-19 4 mo ago modified 2026-10-25 14 d ago also EUVD-2026-41904 , GHSA-q76j-gcg9-vxc6 , GO-2026-5569 , JLSEC-2026-796

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

Hugo is a static site generator. From 0.60.0 until 0.163.3, Hugo's default code-block renderer wrote the Markdown code-fence language or info-string into the code class="language-…" data-lang="…" wrapper without HTML escaping. A fence info-string containing a quote and a script payload breaks out of the attribute and injects a live script element. This issue is fixed in 0.163.3.

Patch / fix

  • go github.com/gohugoio/hugo 0.163.3
  • julia Hugo_jll 0.163.3+0
  • gohugo hugo 0.163.3
  • hugo Debian 14 0.165.0-1

debian advisories DEBIAN-CVE-2026-58402

  • hugo hummingbird 1 0.163.3-0.1.hum1

red hat advisories RHSA-2026:36862

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-58402 updated cvss 5.4

github.com/gohugoio/hugo: Hugo: Cross-site Scripting via unescaped code-fence language in default code block renderer

  • Red Hat Hardened Images hugo 0.163.3-0.1.hum1
    fixed: vendor fix RHSA-2026:36862

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/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
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
OSV 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/gohugoio/hugo
>=0.60.0, <0.163.3
0.163.3
julia Hugo_jll
<0.163.3+0
0.163.3+0

Affected products

  • gohugoio hugo

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.