High [CVE-2026-68763] Denial of Service via HTTP/2 allocation leak
This high-severity Red Hat Linux advisory covers CVE-2026-68763 affecting Red Hat JBoss Web Server 5, Red Hat JBoss Web Server 6, Red Hat JBoss Web Server 7.
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Summary
Uncontrolled Resource Consumption vulnerability in Apache Tomcat via an allocation leak in the HTTP/2 backlog tracking when a stream is reset This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.24, from 10.1.0-M1 through 10.1.57, from 9.0.39 through 9.0.120.
The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.59 through 8.5.100. Other unsupported versions may also be affected.
Users are recommended to upgrade to version 11.0.25, 10.1.58 or 9.0.121, which fix the issue. A remote attacker could exploit this to cause a Denial of Service (DoS), making the server unresponsive or unavailable to users.
This Important flaw in Apache Tomcat, as shipped with Red Hat JBoss Web Server, allows a remote, unauthenticated attacker to cause a denial of service. The vulnerability stems from an allocation leak in the HTTP/2 backlog tracking, which can be triggered by resetting an HTTP/2 stream, leading to resource exhaustion and service unavailability.
Red Hat severity: Important — CVSS 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-770.
Affected Red Hat products: Red Hat JBoss Web Server 5; Red Hat JBoss Web Server 6; Red Hat JBoss Web Server 7.
- 11.0.0
- 11.0.24
- 10.1.0
- 10.1.57
- 9.0.39
- 9.0.120
- 8.5.59
- 8.5.100
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
- 11.0.25
- 10.1.58
- 9.0.121
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- To mitigate this vulnerability, disable the HTTP/2 protocol in Apache Tomcat if it is not required for your deployment. This can be achieved by commenting out or removing the <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" /> element within the <Connector> configuration in the server.xml file. After modifying server.xml, a restart of the Apache Tomcat service is required for the changes to take effect.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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