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Vulnerabilities

Vulnerability · CVE-2011-4858

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 collisio…

Published Jan 5, 2012 · catalog updated Jun 16, 2026 · the affected product

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2011-4858 is not in CISA KEV. FIRST estimates a 79.71% chance of exploitation in the next 30 days. Check whether you run the affected product.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium5.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
79.71%
Remediation
Not established
Affected products
cpe apache/tomcat

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe apache/tomcat5.5.35
  • cpe apache/tomcat6.0.0
  • cpe apache/tomcat6.0.1
  • cpe apache/tomcat6.0.2
  • cpe apache/tomcat6.0.3
  • cpe apache/tomcat6.0.4

How to fix CVE-2011-4858

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2011-4858 is not in CISA KEV. FIRST estimates a 79.71% chance of exploitation in the next 30 days. Check whether you run the affected product.

Which versions are affected?

Compare what you have installed with 5.5.35, 6.0.0, 6.0.1, 6.0.2, 6.0.3, 6.0.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-399. EPSS 79.71%. There is no CISA KEV listing. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Technology hubs

Apache Tomcat security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 5, 2012 · Monitored products — critical

    Detected

    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.

  2. Jun 16, 2026 · Monitored products — critical

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2011-4858

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2011-4858

    30-day exploitation probability 79.71%

    first.org
  • Monitored products — criticalVendor advisoryCVE-2011-4858

    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.

    nvd.nist.gov
  • Metasploit ModulesPublic exploit moduleauxiliary_dos/http/hashcollision_dos

    Public module reference (normal). Module source is not copied into this catalog.

    rapid7.com

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Metasploit ModulesNov 7, 2026
  • FIRST EPSSNov 6, 2026
  • CVE.orgNov 4, 2026
  • Monitored products — criticalNov 3, 2026