---
title: "CVE-2026-68763: Apache Tomcat: DoS via allocation leak in HTTP/2 backlog tracking when a stream is reset"
url: https://erroneo.us/security/cve/CVE-2026-68763/
description: "CVE-2026-68763 (Apache Software Foundation Apache Tomcat): Uncontrolled Resource Consumption vulnerability in Apache Tomcat via an allocation leak in the…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-25
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-68763"
kev: false
cvss: 7.5
epss: 0.00745
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-68763: Apache Tomcat: DoS via allocation leak in HTTP/2 backlog tracking when a stream is reset

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.7% , percentile 54: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Patch this week. Apache Tomcat August 2026: Security Constraint Bypasses — Upgrade Tomcat, including the copy embedded in Spring Boot apps, this week; the access-control bypasses matter wherever you rely on web.xml security constraints or container authentication, and none is known to be exploited.

## What it is

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.

## Affected products (CVE record)

- Apache Software Foundation Apache Tomcat: 11.0.0-M1 <= 11.0.24, 10.1.0-M1 <= 10.1.57, 9.0.39 <= 9.0.120, 8.5.59 <= 8.5.100

## Severity

- CISA-ADP CVSS 3.1: 7.5 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.74% probability of exploitation activity in the next 30 days; percentile 54.

## Sources

- [lists.apache.org](https://lists.apache.org/thread/tv51ty39ppv41v04hdtkp9dp7tg02nzl)
- [CVE.org record CVE-2026-68763](https://www.cve.org/CVERecord?id=CVE-2026-68763)
- [NVD entry CVE-2026-68763](https://nvd.nist.gov/vuln/detail/CVE-2026-68763)
- [openwall.com](http://www.openwall.com/lists/oss-security/2026/08/26/9)

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Source page: https://erroneo.us/security/cve/CVE-2026-68763/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt