What is CVE-2011-3348?

CVE-2011-3348 is a vulnerability in Apache HTTP Server, classified under Uncontrolled Resource Consumption. Published 2011-09-20.

Is CVE-2011-3348 known to be exploited?

12 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Resource exhaustion in Apache HTTP Server

CVE-2011-3348

The mod_proxy_ajp module in the Apache HTTP Server before 2.2.21, when used with mod_proxy_balancer in certain configurations, allows remote attackers to cause a denial of service (temporary "error state" in the backend server) via a malformed HTTP request.

Vulnerability class: DoS (Denial of Service)

Published 2011-09-20 · last modified 2026-06-16.

CVSS v2 metric

CVSS v2 base score 4.3 (Medium). Vector: AV:N/AC:M/Au:N/C:N/I:N/A:P. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.224 (97.6th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.224 · newest: 0.224 · change: 0.000

Affected products

Apache HTTP Server
Red Hat Enterprise Linux — versions 6.0, 7.0
Red Hat Jboss Enterprise Web Server — versions 1.0.0

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

Public proof-of-concept exploits

References

marc.info/ (vendor-advisory, Mailing List, Third Party Advisory, Issue Tracking)
exchange.xforce.ibmcloud.com/vulnerabilities/69804 (VDB Entry, Third Party Advisory, vdb-entry)
support.apple.com/kb/HT5130 (Third Party Advisory)
www.redhat.com/support/errata/RHSA-2011-1391.html (vendor-advisory, Third Party Advisory)
oval.cisecurity.org/repository/search/definition/oval:org.mitre.oval:def:14941 (signature, Third Party Advisory, vdb-entry)
rhn.redhat.com/errata/RHSA-2012-0543.html (vendor-advisory, Third Party Advisory)
marc.info/ (vendor-advisory, Mailing List, Third Party Advisory, Issue Tracking)
www.oracle.com/technetwork/topics/security/cpujuly2013-1899826.html (Third Party Advisory)
www.mandriva.com/security/advisories (vendor-advisory, Broken Link)
lists.apple.com/archives/security-announce/2012/Feb/msg00000.html (vendor-advisory, Mailing List, Broken Link)

Frequently asked questions

What is CVE-2011-3348?: CVE-2011-3348 is a vulnerability in Apache HTTP Server, classified under Uncontrolled Resource Consumption. Published 2011-09-20.
Is CVE-2011-3348 known to be exploited?: 12 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.