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VulnerabilityPublished

CVE-2026-66299: Apache Tomcat · Uncontrolled Resource Consumption

Affects Apache TomcatSource CVE Database V5

0

Not known to be exploited · CVSS 7.5 High · fixed in 11.0.25 : patch Apache Tomcat soon.

Data as of 27 Oct 2026, 05:11 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 11.0.25
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Apache Software FoundationApache TomcatAffected
  • >=11.0.0-M20 <=11.0.24
  • >=10.1.24 <=10.1.57
  • >=9.0.89 <=9.0.120
Fixed in–

AI-suggested

Users should remove the examples web application if it is deployed, as this prevents exposure to the vulnerability. Alternatively, upgrading to Apache Tomcat versions 11.0.25, 10.1.58, or 9.0.121 (when released) will fix the issue.

Description

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web application are not affected by this issue. Users are recommended to remove the examples web application or to upgrade to version 11.0.25, 10.1.58 or 9.0.121 (when released), which fix the issue.

References

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