How severe is CVE-2011-2526?

No CVSS score has been assigned to CVE-2011-2526 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2011-2526?

CVE-2011-2526 affects the following packages: org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat (Maven). Ecosystems affected: Maven.

How do I fix CVE-2011-2526?

Update org.apache.tomcat:tomcat to 5.5.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-2526 is resolved across your whole dependency graph.

How do I detect CVE-2011-2526 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2011-2526 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2011-2526 actively exploited in the wild?

No public exploit code has been indexed for CVE-2011-2526 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2011-2526?

CVE-2011-2526 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 53th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2011-2526?

CVE-2011-2526 is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2011-2526 published, and has it been updated?

CVE-2011-2526 was published on May 14, 2022 and was last updated on February 21, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2011-2526 — tomcat

Fix: apache/tomcat@1d372c8

CVE-2011-2526 is a Improper Input Validation vulnerability in org.apache.tomcat:tomcat. A fix is available for org.apache.tomcat:tomcat — see the affected versions and patch details below.

Improper Input Validation in Apache Tomcat

Published

May 14, 2022

Updated

Feb 21, 2024

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs53th percentile — riskier than 53% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

3 pkgs affected

☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat☕org.apache.tomcat:tomcat

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Apache Tomcat 5.5.x before 5.5.34, 6.x before 6.0.33, and 7.x before 7.0.19, when sendfile is enabled for the HTTP APR or HTTP NIO connector, does not validate certain request attributes, which allows local users to bypass intended file access restrictions or cause a denial of service (infinite loop or JVM crash) by leveraging an untrusted web application.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.tomcat:tomcat`	all versions	5.5.34`org.apache.tomcat:tomcat:5.5.34`
☕Maven	`org.apache.tomcat:tomcat`	≥ 6.0.0&&< 6.0.33	6.0.33`org.apache.tomcat:tomcat:6.0.33`
☕Maven	`org.apache.tomcat:tomcat`	≥ 7.0.0&&< 7.0.19	7.0.19`org.apache.tomcat:tomcat:7.0.19`

Affected Products

1 product · 80 configurations

Application

tomcatapache

79 versions

5.5.05.5.15.5.25.5.35.5.45.5.55.5.65.5.75.5.85.5.95.5.105.5.11

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.tomcat:tomcat, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.tomcat:tomcat to 5.5.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2011-2526 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

The Red Hat Security Response Team has rated this issue as having low security impact, a future update may address this flaw.

Product	Fixed in	Advisory
JBEWP 5 for RHEL 5	`jbossweb-0:2.1.12-3_patch_03.2.ep5.el5`	RHSA-2012:0076
JBoss Communications Platform 5.1	see advisory	RHSA-2012:0078
JBoss Enterprise BRMS Platform 5.1	see advisory	RHSA-2012:0325
Red Hat Enterprise Linux 6	`tomcat6-0:6.0.24-35.el6_1`	RHSA-2011:1780
Red Hat JBoss Enterprise Application Platform 4.3	see advisory	RHSA-2012:0041
Red Hat JBoss Enterprise Application Platform 5.1	see advisory	RHSA-2012:0075
Red Hat JBoss Enterprise Application Platform 5 for RHEL 5	`jbossweb-0:2.1.12-3_patch_03.2.ep5.el5`	RHSA-2012:0074
Red Hat JBoss Enterprise Web Server 1 for RHEL 5	`tomcat5-0:5.5.33-27_patch_07.ep5.el5`	RHSA-2012:0680

Ubuntu

USN-1252-1Ubuntu

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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