Skip to content
Noroxi
NVD / CVE Program· CNA redhat

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…

MediumCVSS 4.3 · v2.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 24/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 22.3% (FIRST EPSS); higher than 97.7% of all records.
  • Fixed version: apache2 (Debian:12) 2.2.21-1; httpd (Red Hat:enterprise_linux:6::server) 0:2.2.15-9.el6_1.3; httpd-debuginfo (Red Hat:enterprise_linux:6::server) 0:2.2.15-9.el6_1.3.

Low priority for now. Upgrade to apache2 (Debian:12) 2.2.21-1; httpd (Red Hat:enterprise_linux:6::server) 0:2.2.15-9.el6_1.3; httpd-debuginfo (Red Hat:enterprise_linux:6::server) 0:2.2.15-9.el6_1.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Sep 20, 2011
Updated
Jun 16, 2026
EPSS
22.3% · 97th percentile

Report tools

JSON

Action score

24

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
7 / 30 · 22.3%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2011-3348

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Is Apache HTTP Server on your server exposed to the internet?Run a port scan

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for apache records

Is Apache HTTP Server on your server exposed to the internet?Run a port scan

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
apachehttp server
redhatjboss enterprise web server
redhatenterprise linux

Using http server? Add it to your stack and be the first to know about CVEs like this one. (Apache HTTP)

Watch new CVEs for http server

When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or is weaponized

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Is Apache HTTP Server on your server exposed to the internet?Run a port scan

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every Monday

Is Apache HTTP Server on your server exposed to the internet?

The free port scanner finds the open ports on your server and matches the service versions it can read against known vulnerabilities. No account needed.

Run a port scan

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache http server2.2.12 and later · up to 2.2.20 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12apache2before 2.2.21-12.2.21-1
Red Hat:enterprise_linux:6::serverhttpdbefore 0:2.2.15-9.el6_1.30:2.2.15-9.el6_1.3
Red Hat:enterprise_linux:6::serverhttpd-debuginfobefore 0:2.2.15-9.el6_1.30:2.2.15-9.el6_1.3
Red Hat:enterprise_linux:6::serverhttpd-develbefore 0:2.2.15-9.el6_1.30:2.2.15-9.el6_1.3
Red Hat:enterprise_linux:6::serverhttpd-manualbefore 0:2.2.15-9.el6_1.30:2.2.15-9.el6_1.3
Red Hat:enterprise_linux:6::serverhttpd-toolsbefore 0:2.2.15-9.el6_1.30:2.2.15-9.el6_1.3
Red Hat:enterprise_linux:6::servermod_sslbefore 1:2.2.15-9.el6_1.31:2.2.15-9.el6_1.3
Red Hat:jboss_enterprise_web_server:1::el5httpdbefore 0:2.2.17-15.4.ep5.el50:2.2.17-15.4.ep5.el5
Red Hat:jboss_enterprise_web_server:1::el5httpd-develbefore 0:2.2.17-15.4.ep5.el50:2.2.17-15.4.ep5.el5
Red Hat:jboss_enterprise_web_server:1::el5httpd-manualbefore 0:2.2.17-15.4.ep5.el50:2.2.17-15.4.ep5.el5
Red Hat:jboss_enterprise_web_server:1::el5mod_sslbefore 1:2.2.17-15.4.ep5.el51:2.2.17-15.4.ep5.el5
Red Hat:jboss_enterprise_web_server:1::el6httpdbefore 0:2.2.17-15.4.ep5.el60:2.2.17-15.4.ep5.el6
Red Hat:jboss_enterprise_web_server:1::el6httpd-develbefore 0:2.2.17-15.4.ep5.el60:2.2.17-15.4.ep5.el6
Red Hat:jboss_enterprise_web_server:1::el6httpd-manualbefore 0:2.2.17-15.4.ep5.el60:2.2.17-15.4.ep5.el6
Red Hat:jboss_enterprise_web_server:1::el6httpd-toolsbefore 0:2.2.17-15.4.ep5.el60:2.2.17-15.4.ep5.el6
Red Hat:jboss_enterprise_web_server:1::el6mod_sslbefore 1:2.2.17-15.4.ep5.el61:2.2.17-15.4.ep5.el6

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-42013Path Traversal and Remote Code Execution in Apache HTTP Server 2.4.49 and 2.4.50 (incomplete fix of CVE-2021-41773)KEV
    99Now
  • CVE-2021-41773Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49KEV
    99Now
  • CVE-2024-38475Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path.KEV
    96Now

Published before and after this one in the same product

  • ← EarlierCVE-2011-2688Jul 28, 2011 · SQL injection vulnerability in mysql/mysql-auth.pl in the mod_authnz_external module 3.2.5 and earlier for the Apache HTTP Server allows…
    32Monitor
  • ← EarlierCVE-2011-3192Aug 29, 2011 · The byterange filter in the Apache HTTP Server 1.3.x, 2.0.x through 2.0.64, and 2.2.x through 2.2.19 allows remote attackers to cause a…
    61This week
  • Later →CVE-2011-3368Oct 5, 2011 · The mod_proxy module in the Apache HTTP Server 1.3.x through 1.3.42, 2.0.x through 2.0.64, and 2.2.x through 2.2.21 does not properly…
    47Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:apache22.2.21-1 · Debian:12Package registry (OSV)
red hat:httpd0:2.2.15-9.el6_1.3 · Red Hat:enterprise_linux:6::serverPackage registry (OSV)
red hat:httpd-debuginfo0:2.2.15-9.el6_1.3 · Red Hat:enterprise_linux:6::serverPackage registry (OSV)
red hat:httpd-devel0:2.2.15-9.el6_1.3 · Red Hat:enterprise_linux:6::serverPackage registry (OSV)
red hat:httpd-manual0:2.2.15-9.el6_1.3 · Red Hat:enterprise_linux:6::serverPackage registry (OSV)
red hat:httpd-tools0:2.2.15-9.el6_1.3 · Red Hat:enterprise_linux:6::serverPackage registry (OSV)
red hat:mod_ssl1:2.2.15-9.el6_1.3 · Red Hat:enterprise_linux:6::serverPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

    If successful

    Confidentiality
    none
    Integrity
    none
    Availability
    P · the service can be disrupted
    Attack complexity
    M
    Confidentiality impact
    None
    Integrity impact
    None
    Availability impact
    P

    Weakness class (CWE)

    CWE-400 · Uncontrolled Resource Consumption

    CVSS vector

    AV:N/AC:M/Au:N/C:N/I:N/A:P

    nvd-primary

    Root cause

    Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

    The bug in code

    The whole CWE-400 class

    A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

    Vulnerable

    ts
    function expand(node) {  return node.children.map(expand);}

    Fixed

    ts
    const MAX_DEPTH = 32;function expand(node, depth = 0) {  if (depth > MAX_DEPTH) throw new Error("too deep");  return node.children.map((c) => expand(c, depth + 1));}

    Attack context

    MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

    References

    Show all references (19 more)

    Vendor advisories and official records. Exploit/PoC links are deliberately left out.

    All records