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Vulnerabilities

Vulnerability · CVE-2016-2161

In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequ…

Published Jul 27, 2017 · catalog updated Jun 17, 2026 · http server

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

Check this week

CVE-2016-2161 is not in CISA KEV. FIRST estimates a 20.95% chance of exploitation in the next 30 days. Check whether you run http server.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
20.95%
Remediation
Not established
Affected products
cpe apache/http server

In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequently valid requests.

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/http server2.4.0
  • cpe apache/http server2.4.1
  • cpe apache/http server2.4.2

How to fix CVE-2016-2161

What to do

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

Should you patch?

CVE-2016-2161 is not in CISA KEV. FIRST estimates a 20.95% chance of exploitation in the next 30 days. Check whether you run http server.

Which versions are affected?

Compare what you have installed with apache/http server 2.4.0; apache/http server 2.4.1; apache/http server 2.4.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation; CWE-823. EPSS 20.95%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Apache HTTP Server 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.

No dated events have been recorded yet.

Sources

  • CVE.orgVulnerability recordCVE-2016-2161

    Official CVE identifier

    cve.org
  • Monitored products — criticalVendor advisoryCVE-2016-2161

    In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequently valid requests.

    nvd.nist.gov

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 4, 2026
  • Monitored products — criticalNov 4, 2026