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.)

jsoup is a Java library for working with HTML. Those using jsoup versions prior to 1.14.2 to parse untrusted HTML or XML may be vulnerable to DOS attacks. If the parser is run on user supplied input, an attacker may supply content that causes the parser to get stuck (loop indefinitely until cancelled), to complete more slowly than usual, or to throw an unexpected exception. This effect may support a denial of service attack. The issue is patched in version 1.14.2. There are a few available workarounds. Users may rate limit input parsing, limit the size of inputs based on system resources, and/or implement thread watchdogs to cap and timeout parse runtimes.

Cross-site scripting (XSS) vulnerability in jsoup before 1.8.3.