Stored XSS via unescaped code-fence language
Published Jul 6, 2026 · Updated Jul 6, 2026
Stored XSS in Hugo 0.60.0 through 0.163.2 allows attackers to inject browser scripts through crafted Markdown code fences. The default code-block renderer concatenates the unescaped fence language into class and data-lang attributes, so a quote closes the attribute and emits a script element. Exploitation requires untrusted content to enter a site build and a visitor to load the generated page, exposing that visitor's browser context.
Summary
What happened
Stored XSS in Hugo 0.60.0 through 0.163.2 allows attackers to inject browser scripts through crafted Markdown code fences. The default code-block renderer concatenates the unescaped fence language into class and data-lang attributes, so a quote closes the attribute and emits a script element. Exploitation requires untrusted content to enter a site build and a visitor to load the generated page, exposing that visitor's browser context.
The record
- CVE
- CVE-2026-58402
- Published
- Jul 6, 2026
- Updated
- Jul 6, 2026
- Vendor
- Hugo Authors
- Product
- Hugo
- Classifications
- CWE-79, T1189
- Attack vector
- network
- Privileges
- Unavailable
Timeline
How it unfolded
- Jul 6, 2026CVE publishedPublication date reported by the CVE source.
- Jul 6, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 0.60.0, < 0.163.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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