CVE-2009-0816

Typo3 Backend XSS Vulnerability

An Information Disclosure vulnerability in jumpUrl mechanism, used to track access on web pages and provided files, allows a remote attacker to read arbitrary files on a host.

The expected value of a mandatory hash secret, intended to invalidate such requests, is exposed to remote users allowing them to bypass access control by providing the correct value.

There's no authentication required to exploit this vulnerability. The vulnerability allows to read any file, the web server user account has access to.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

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1. What is CVE-2009-0816? CVE-2009-0816 is a medium-severity cross-site scripting (XSS) vulnerability in typo3/cms (composer), affecting versions >= 3.3.0, < 3.9.0. It is fixed in 4.0.12, 4.1.10, 4.2.6. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. Which versions of typo3/cms are affected by CVE-2009-0816? typo3/cms (composer) versions >= 3.3.0, < 3.9.0 is affected.
3. Is there a fix for CVE-2009-0816? Yes. CVE-2009-0816 is fixed in 4.0.12, 4.1.10, 4.2.6. Upgrade to this version or later.
4. Is CVE-2009-0816 exploitable, and should I be worried? Whether CVE-2009-0816 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2009-0816 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2009-0816?
   • Upgrade typo3/cms to 4.0.12 or later
   • Upgrade typo3/cms to 4.1.10 or later
   • Upgrade typo3/cms to 4.2.6 or later

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