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High severity · published Sep 23, 2026
CVE-2026-79677
Apache Tomcat: WebSocket DoS due to lost asynchronous write timeout
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
Tomcat · Apache
11.0.0-M1 through 11.0.25; 10.1.0-M1 through 10.1.59; 9.0.0.M1 through 9.0.121; 8.5.0 through 8.5.100; 7.0.43 through 7.0.109 · source: vendor
Affected product
TO
Tomcat
Apache
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-79677
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-79677
lists.apache.org
https://lists.apache.org/thread/bzwps6ck4szf2hmksbbon3syyl9qnkv8
www.openwall.com
http://www.openwall.com/lists/oss-security/2026/09/23/27
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