CVE-2022-36033: jsoup may not sanitize Cross-Site Scripting (XSS) attempts if SafeList.preserveRelativeLinks is enabled

Vulnerability summary

CVE-2022-36033 is a medium (CVSS 6.1) vulnerability in jhy jsoup. EPSS estimates a 1.64% chance of exploitation in the next 30 days, higher than 76.4% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 29-08-2022
   PublishedVulnerability first disclosed.
2. 22-04-2025
   Last modifiedVulnerability information updated.

Description

jsoup is a Java HTML parser, built for HTML editing, cleaning, scraping, and cross-site scripting (XSS) safety. jsoup may incorrectly sanitize HTML including `javascript:` URL expressions, which could allow XSS attacks when a reader subsequently clicks that link. If the non-default `SafeList.preserveRelativeLinks` option is enabled, HTML including `javascript:` URLs that have been crafted with control characters will not be sanitized. If the site that this HTML is published on does not set a Content Security Policy, an XSS attack is then possible. This issue is patched in jsoup 1.15.3. Users should upgrade to this version. Additionally, as the unsanitized input may have been persisted, old content should be cleaned again using the updated version. To remediate this issue without immediately upgrading: - disable `SafeList.preserveRelativeLinks`, which will rewrite input URLs as absolute URLs - ensure an appropriate [Content Security Policy](https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP) is defined. (This should be used regardless of upgrading, as a defence-in-depth best practice.)

• CWE-79Improper Neutralization of Input During Web Page GenerationThe product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
• CWE-87Improper Neutralization of Alternate XSS SyntaxThe product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax.