CVE-2026-77791

Apache Tomcat: DoS via busy wait during WebSocket close

At a glance

Severity: HIGH 7.5
EPSS: EPSS 0.68 % · percentile 52 (2026-10-27)
State: PUBLISHED
Published: 2026-09-23
Updated: 2026-09-23
Assigner: apache
NVD status: Awaiting Analysis

Description

Uncontrolled Resource Consumption vulnerability in Apache Tomcat during sending of WebSocket close message enabled a DoS attack. This issue affects Apache Tomcat: from 11.0.0-M5 through 11.0.25, from 10.1.8 through 10.1.59, from 9.0.74 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.88 through 8.5.100. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CISA-ADP
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Weaknesses (CWE)

CWE-400

European references

ENISA EUVD · EUVD-2026-85229
GCVE · GCVE-0-2026-77791

CERT-FR advisories

CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
CERTFR-2026-AVI-1336 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1218 — Multiples vulnérabilités dans Apache Tomcat · cert.ssi.gouv.fr

Affected products

Product	Versions
Apache Software Foundation · Apache Tomcat	affected 11.0.0-M5 ≤ 11.0.25 ; affected 10.1.8 ≤ 10.1.59 ; affected 9.0.74 ≤ 9.0.121 ; affected 8.5.88 ≤ 8.5.100 ; unaffected 0 ≤ 7.0.109

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD