CVE-2026-78437

Apache Tomcat: HTTP/2 DoS via malformed request

At a glance

Severity: HIGH 7.3
EPSS: EPSS 0.51 % · percentile 43 (2026-10-27)
State: PUBLISHED
Published: 2026-09-23
Updated: 2026-09-23
Assigner: apache
NVD status: Awaiting Analysis

Description

Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail. This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121. 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 7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	CISA-ADP
CVSS 3.1	HIGH 7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L	NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Weaknesses (CWE)

CWE-459

European references

ENISA EUVD · EUVD-2026-85231
GCVE · GCVE-0-2026-78437

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 11.0.19 ≤ 11.0.25 ; affected 10.1.53 ≤ 10.1.59 ; affected 9.0.116 ≤ 9.0.121 ; unaffected 0 ≤ 8.5.100

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