Cross-Site Scripting in Prism
Impact
The easing preview of the Previewers plugin has an XSS vulnerability that allows attackers to execute arbitrary code in Safari and Internet Explorer.
This impacts all Safari and Internet Explorer users of Prism >=v1.1.0 that use the Previewers plugin (>=v1.10.0) or the Previewer: Easing plugin (v1.1.0 to v1.9.0).
Patches
This problem is patched in v1.21.0.
Workarounds
To workaround the issue without upgrading, disable the easing preview on all impacted code blocks. You need Prism v1.10.0 or newer to apply this workaround.
References
The vulnerability was introduced by this commit on Sep 29, 2015 and fixed by Masato Kinugawa (#2506).
For more information
If you have any questions or comments about this advisory, please open an issue.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | prismjs | >= 1.1.0, < 1.21.0 | 1.21.0 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L- Weakness (CWE)
CWE-79- Platform
- npm
- Package
prismjs- Disclosed
- 07.08.2020
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-wvhm-4hhf-97x9 - CC BY 4.0
Vulnerability history: prismjs
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
- 6
- First → latest
- 08.2020 03.2025
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Medium 2
Disclosures per year
- 2020: 1
- 2021: 3
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 0
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