CVE-2011-4858
CVE-2011-4858 is a CWE-399 vulnerability in apache tomcat. 2 public exploit references exist, so weaponization risk is real. O3 Security detects and blocks CVE-2011-4858 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably,…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
Apache Tomcat before 5.5.35, 6.x before 6.0.35, and 7.x before 7.0.23 computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters.
Affected Products
tomcatapacheResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
MyBulletinBoard (MyBB) 1.1.5 - 'CLIENT-IP' SQL Injection
by rgod · Jul 15, 2006
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every apache tomcat 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-2011-4858 yet — track the apache tomcat 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-2011-4858 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-2011-4858. 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-2011-4858 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2011-4858 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.