CVE-2015-5956
CVE-2015-5956 is a Cross-site Scripting (XSS) vulnerability in typo3 typo3. O3 Security detects and blocks CVE-2015-5956 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
The sanitizeLocalUrl function in TYPO3 6.x before 6.2.15, 7.x before 7.4.0, 4.5.40, and earlier allows remote authenticated users to bypass the XSS filter and conduct cross-site scripting…
Description
The sanitizeLocalUrl function in TYPO3 6.x before 6.2.15, 7.x before 7.4.0, 4.5.40, and earlier allows remote authenticated users to bypass the XSS filter and conduct cross-site scripting (XSS) attacks via a base64 encoded data URI, as demonstrated by the (1) returnUrl parameter to show_rechis.php and the (2) redirect_url parameter to index.php.
Affected Products
typo3typo3Detection & mitigation playbook
Vendor / applianceDetect
Inventory every typo3 typo3 deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Remediation status
No patch has shipped for CVE-2015-5956 yet — track the typo3 typo3 advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2015-5956 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2015-5956. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2015-5956 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2015-5956 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.