CVE-2026-66299General(apache / tomcat)

LOWCVSS 5.3 · MEDIUM

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch apache tomcat systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD 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.

0.5/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-400

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • tomcat

Threat summary

  • Patch or workaround signal is available
  • 6 mentions across 5 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 4 signals
  • General: 4 classified signals
  • Disclosure: 1 classified signal
  • Peaked 3d ago at 2 mentions (2026-07-29); latest day: 1
  • 6 total mentions across 5 days

Affected systems

Vendors
Products
tomcat

1 version affected across 1 product

Deep dive

Activity timeline6 mentions / 5d
01122Mentions · 2026-07-28: 1Mentions · 2026-07-29: 2Mentions · 2026-07-31: 1Mentions · 2026-08-01: 1Mentions · 2026-08-03: 1Patch / Workaround · 2026-07-29: 1Technical Details · 2026-07-28: 1Technical Details · 2026-07-31: 1Technical Details · 2026-08-01: 1Technical Details · 2026-08-03: 107-2807-2907-3108-0108-03
Signal classification3 categories
General
466.7%
Disclosure
116.7%
Patch
116.7%
Referenced assets3 URLs
Classification over time
DateTotalLabels
2026-07-281
Disclosure1
2026-07-292
General1Patch1
2026-07-311
General1
2026-08-011
General1
2026-08-031
General1
Full discourse6 posts
  • Johan Hutting@JohanHutting
    Patch

    Guess I'm one of the few who thinks it was a good move to not release a fix for CVE-2026-66299 on the tomcat-example site 😅 It's unfortunately also clear that many blindly update dependencies rather than look at what a CVE's impact is.

    Post summary

    The tweet offers a sarcastic opinion that it was a good decision not to release a fix for CVE‑2026‑66299, highlighting concerns about automatic dependency updates.

    0001068
    187 followersView on X
  • VulDB 🛡@vuldb
    General

    It is possible to see elevated activities targeting Apache Tomcat (CVE-2026-66299) https://vuldb.com/vuln/383887/cti

    Post summary

    The post references elevated activity around Apache Tomcat CVE-2026-66299 but provides no PoC, exploit, patch, or evidence of active exploitation.

    0000191
    2.3K followersView on X
  • ゆぅさん@YY20424277
    General

    【3軸解説】「Apache TomcatのWebSocket chatサンプルにおけるサービス運用妨害(DoS)の脆弱性(2026年7月28日)(CVE-2026-66299)」を、背景 / 目的 / 効果 の 3 軸で読み解きます。 背景/目的/効果の3軸で読み解きました。 #セキュリティ #若手コン… ▶ 無料ツール WR-Analysis: https://www.intect-i.jp/tools/wr-analysis/?utm_source=sns&utm_medium=social&utm_campaign=wr_analysis

    Post summary

    The post mentions CVE-2026-66299 as a DoS flaw in Apache Tomcat’s WebSocket chat sample but provides only a high-level overview without PoC, exploit code, or patch information.

    0000059
    844 followersView on X
  • ゆぅさん@YY20424277
    General

    【3軸解説】「Apache TomcatのWebSocket chatサンプルにおけるサービス運用妨害(DoS)の脆弱性(2026年7月28日)(CVE-2026-66299)」を、背景 / 目的 / 効果 の 3 軸で読み解きます。 背景/目的/効果の3軸で読み解きました。 #セキュリティ #若手コン… ▶ 無料ツール WR-Analysis: https://www.intect-i.jp/tools/wr-analysis/?utm_source=sns&utm_medium=social&utm_campaign=wr_analysis

    Post summary

    The post delivers a concise overview of CVE-2026-66299, describing it as a DoS issue in Apache Tomcat's WebSocket chat sample, without providing PoC, exploit code, or patch details.

    0000067
    844 followersView on X
  • ゆぅさん@YY20424277
    General

    【3軸解説】「Apache TomcatのWebSocket chatサンプルにおけるサービス運用妨害(DoS)の脆弱性(2026年7月28日)(CVE-2026-66299)」を、背景 / 目的 / 効果 の 3 軸で読み解きます。 背景/目的/効果の3軸で読み解きました。 #セキュリティ #若手コン… ▶ 無料ツール WR-Analysis: https://www.intect-i.jp/tools/wr-analysis/?utm_source=sns&utm_medium=social&utm_campaign=wr_analysis

    Post summary

    The post provides a brief analysis of a recently disclosed DoS vulnerability (CVE‑2026‑66299) in Apache Tomcat’s WebSocket chat sample, but does not include a PoC, exploit code, active exploitation evidence, or patch information.

    0000071
    844 followersView on X
  • Vulmon Vulnerability Feed@VulmonFeeds
    Disclosure

    CVE-2026-66299 Uncontrolled Resource Consumption in Apache Tomcat WebSocket Chat Example https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-66299

    Post summary

    CVE-2026-66299 is disclosed as an uncontrolled resource consumption issue in Apache Tomcat's WebSocket chat example, with additional details available via the provided link.

    0000099
    4.1K followersView on X
CPE platform detail8 entries

8 of 8 entries

PartVendorProductVersionTarget SWTarget HW
Appapachetomcat---
Appapachetomcat11.0.0--
Appapachetomcat11.0.0--
Appapachetomcat11.0.0--
Appapachetomcat11.0.0--
Appapachetomcat11.0.0--
Appapachetomcat11.0.0--
Appapachetomcat11.0.0--

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