Vulnerability in Apache Tomcat (July 29, 2026)

unknownCVE-2026-66299

A vulnerability has been discovered in Apache Tomcat. It allows an attacker to cause a remote denial of service.

CSIRTS triage

vendor: Apache product: Tomcat Denial of service

What: A vulnerability allows remote denial of service.
Who is affected: Deployments of Apache Tomcat are affected.
Urgency: Remediation is necessary due to the potential for denial of service.
Action: Apply patches as they become available.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CERT-FR Avis de sécurité (FR · national-cert · site)
Severity: unknown
Published: 2026-07-29
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-0940/

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-662990.31% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 23% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-66299	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Apache Tomcat

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[NEW] [medium] Apache Tomcat: Multiple vulnerabilitiescert-bund · 2026-07-31
medium[NEW] [medium] Apache Tomcat: Vulnerability allows Denial of Servicecert-bund · 2026-07-29
criticalCVE-2026-66713: Deserialization of Untrusted Data (CWE-502) in the Tribes-based clustering component in Apache…nvd · 2026-07-28
highCVE-2026-66299: Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. Thi…nvd · 2026-07-28
high[UPDATE] [high] Apache Tomcat and Tomcat Native: Multiple vulnerabilitiescert-bund · 2026-07-27
medium[UPDATE] [medium] Apache Tomcat and Tomcat Native: Multiple vulnerabilitiescert-bund · 2026-07-27