CVE-2026-79677

Apache Tomcat: WebSocket DoS due to lost asynchronous write timeout

HIGH
7.5
CVSS Score
Published: September 23, 2026 at 11:28 AM UTC
Updated: September 23, 2026 at 07:30 PM UTC
1 product affected across 1 vendorTomcat

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

Missing release of resource after effective lifetime, Comparison using wrong factors vulnerability in Apache Tomcat allows a denial of service as a result of lost time outs for asynchronous WebSocket writes. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121. The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.43 through 7.0.109. 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

10.1.0-M1 ≤ v ≤ 10.1.5911.0.0-M1 ≤ v ≤ 11.0.257.0.43 ≤ v ≤ 7.0.1098.5.0 ≤ v ≤ 8.5.1009.0.0.M1 ≤ v ≤ 9.0.12110.1.0-M111.0.0-M17.0.438.5.09.0.0.M1
Vendor states this is fixed in 7.0.43 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-772CWE-1025

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