What’s Vulnerable › Vulnerabilities

CVE-2021-39286

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-18 · updated 2026-06-17
• Weakness: CWE-79

Description

Webrecorder pywb before 2.6.0 allows XSS because it does not ensure that Jinja2 templates are autoescaped.

Affected products

• webrecorder Pywb: before 2.6.0 — fixed in 2.6.0

How to fix

Upgrade to a fixed version: webrecorder Pywb 2.6.0. Check the vendor advisory for mitigations.

References

• https://github.com/webrecorder/pywb/commit/f7bd84cdacdd665ff73ae8d09a202f60be2ebae9
• https://github.com/webrecorder/pywb/compare/v-2.5.0...v-2.6.0
• https://github.com/webrecorder/pywb/commit/f7bd84cdacdd665ff73ae8d09a202f60be2ebae9
• https://github.com/webrecorder/pywb/compare/v-2.5.0...v-2.6.0

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