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HighVulnerabilityupdated 30 Oct 2026, 14:17 UTC

Apache Tomcat: several flaws let remote attackers bypass security or crash the server

Attackers on the internet may be able to get around protections, read data they should not see, change data, or overload the Tomcat web server so it stops working. The exact fixed versions are not named in the material.

Official source
SeverityHighVulnerability
Being exploited?UnclearNo reports either way yet
Fix available?UnclearNo fixed version published in the sources yet
How sure is this?Official sourceBacked by an official source

What happened

Multiple vulnerabilities in Apache Tomcat can be exploited remotely to bypass security measures, disclose information, manipulate data, or cause denial of service; some further attacks are unspecified.

Why it is dangerous: Websites and applications running on Tomcat may be taken offline or have sensitive information exposed, and any internet-facing Tomcat server is at risk.

Are you affected?

You are affected if you run Apache Tomcat in a version listed as affected by the CERT-Bund advisory, especially if it is reachable from the internet.

What to do

  1. Check which Tomcat version you run and compare it with the vendor advisory
  2. Update Apache Tomcat to the fixed version named in the official Apache advisory
  3. Restrict external access to the Tomcat server until the update is applied

Timeline

  1. 30 Oct 2026, 10:49 UTC
    Publicly disclosed
  2. 30 Oct 2026, 10:49 UTC
    Reported by CERT-Bund (BSI) · CERT-Bund (BSI)
  3. 30 Oct 2026, 10:50 UTC
    Picked up by Zero Radar
  4. 30 Oct 2026, 14:15 UTC
    Reported by CERT-Bund (BSI) · CERT-Bund (BSI)

Sources 2 reports, oldest first

Official vendor, government CERT or advisory database

Technical details

ID
ZR-7c1418b4
Disclosed
30 Oct 2026, 10:49 UTC
On Zero Radar
30 Oct 2026, 10:50 UTC (1 min after disclosure)
Last change
30 Oct 2026, 14:17 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works

Apache Tomcat: several flaws let remote attackers bypass security or crash the server · Zero Radar