# CVE-2026-68763: Apache Tomcat resource exhaustion in HTTP/2 backlog tracking

Source: https://junglewise.ai/threats/cve-2026-68763-apache-tomcat-resource-exhaustion-in-http-2-backlog-tracking  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-25. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-68763 · Severity: high · CVSS 7.5 · Published 2026-08-25

Apache Tomcat is a widely-used web application server that processes incoming HTTP requests. A memory leak in its HTTP/2 stream handling allows an attacker to exhaust server memory by repeatedly sending and resetting HTTP/2 streams, causing the service to become unavailable. This can lead to unplanned service outages and disrupt web applications running on affected Tomcat instances.

Technologies: [Apache Tomcat](https://junglewise.ai/threats/technologies/tomcat). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-68763 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-68763 being exploited in the wild.

**How severe is CVE-2026-68763?** High severity, with a CVSS score of 7.5, published 25 August 2026.

**Which products and versions are affected?** Apache Tomcat 11.0.0-M1 through 11.0.24, 10.1.0-M1 through 10.1.57, 9.0.39 through 9.0.120, 8.5.59 through 8.5.100.

**Is there a fix for CVE-2026-68763?** A patch was published on 2026-08-25: Fixes available in versions 11.0.25, 10.1.58, and 9.0.121 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-68763 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-68763?** Check whether you run Apache Tomcat at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

This is an uncontrolled resource consumption (denial-of-service) vulnerability in Apache Tomcat's HTTP/2 implementation. The root cause is an allocation leak in the backlog tracking mechanism that occurs when an HTTP/2 stream is reset. When a stream is reset, the backlog memory is not properly freed, allowing an attacker to trigger multiple stream resets and exhaust available memory without authentication or special network positioning (network-accessible HTTP/2 endpoint). Affected versions include 11.0.0-M1 through 11.0.24, 10.1.0-M1 through 10.1.57, 9.0.39 through 9.0.120, and EOL versions 8.5.59 through 8.5.100. Fixes are available in versions 11.0.25, 10.1.58, and 9.0.121.

## Affected products

- Apache Tomcat 11.0.0-M1 through 11.0.24, 10.1.0-M1 through 10.1.57, 9.0.39 through 9.0.120, 8.5.59 through 8.5.100

## Timeline

- 2026-08-25: disclosed
- 2026-08-25: patched: Fixes available in versions 11.0.25, 10.1.58, and 9.0.121

## References

- [https://lists.apache.org/thread/tv51ty39ppv41v04hdtkp9dp7tg02nzl](https://lists.apache.org/thread/tv51ty39ppv41v04hdtkp9dp7tg02nzl)
- [http://www.openwall.com/lists/oss-security/2026/08/26/9](http://www.openwall.com/lists/oss-security/2026/08/26/9)

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