What’s Vulnerable › Vulnerabilities

CVE-2021-21610

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-01-13 · updated 2026-06-17
• Weakness: CWE-79

Description

Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not implement any restrictions for the URL rendering a formatted preview of markup passed as a query parameter, resulting in a reflected cross-site scripting (XSS) vulnerability if the configured markup formatter does not prohibit unsafe elements (JavaScript) in markup.

Affected products

• Jenkins: through 2.263.1; through 2.274

References

• https://www.jenkins.io/security/advisory/2021-01-13/#SECURITY-2153
• https://www.jenkins.io/security/advisory/2021-01-13/#SECURITY-2153

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