Next.js has cross-site scripting in beforeInteractive scripts with untrusted input
Impact
Applications that use beforeInteractive scripts together with untrusted content can be vulnerable to cross-site scripting. In affected versions, serialized script content was not escaped safely before being embedded into the document, which could allow attacker-controlled input to break out of the intended script context and execute arbitrary JavaScript in a visitor's browser.
Fix
We now HTML-escape serialized beforeInteractive script content before embedding it into the page, preventing attacker-controlled content from breaking out of the inline script boundary.
Workarounds
If you cannot upgrade immediately, do not pass untrusted data into beforeInteractive scripts. If that pattern is unavoidable, sanitize or escape the content before embedding it.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | next | >= 13.0.0, < 15.5.16, >= 16.0.0, < 16.2.5 | 15.5.16, 16.2.5 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-79- Platform
- npm
- Package
next- Disclosed
- 11.05.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-gx5p-jg67-6x7h - CC BY 4.0
Vulnerability history: next
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 73
- First → latest
- 12.2017 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 5
- High 27
- Medium 32
- Low 9
Disclosures per year
- 2017: 1
- 2018: 2
- 2019: 0
- 2020: 3
- 2021: 3
- 2022: 3
- 2023: 1
- 2024: 6
- 2025: 14
- 2026: 40
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Next.js has cross-site scripting in beforeInteractive scripts with untrusted input this entry
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