Apache Tomcat: DoS via malformed HTTP/2 PRIORITY_UPDATE frame (CVE-2025-31650)
Description
Apache Tomcat contains an improper input validation vulnerability in handling malformed HTTP/2 PRIORITY_UPDATE frames. This flaw causes incorrect error handling for some invalid HTTP priority headers, leading to incomplete cleanup of failed requests and a memory leak. A large number of such requests can trigger an OutOfMemoryException, resulting in a denial of service. The issue affects multiple versions across Tomcat 8.5, 9.0, 10.1, and 11.0 branches. Fixed versions have been released to address this vulnerability.
Affected software
pkg:bitnami/tomcatRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2025-31650 is an improper input validation vulnerability in Apache Tomcat that arises from incorrect error handling of malformed HTTP/2 PRIORITY_UPDATE frames. Specifically, invalid HTTP priority headers cause incomplete cleanup of failed requests, creating a memory leak. When exploited by sending many such malformed requests, this can exhaust memory and cause an OutOfMemoryException, leading to denial of service. The affected versions include 8.5.90 through 8.5.100 (EOL), 9.0.76 through 9.0.102, 10.1.10 through 10.1.39, and 11.0.0 through 11.0.5. Users are advised to upgrade to fixed versions 9.0.104, 10.1.40, or 11.0.6.
Potential Impact
The vulnerability can cause a denial of service by exhausting server memory through a memory leak triggered by malformed HTTP/2 PRIORITY_UPDATE frames. This results in an OutOfMemoryException that disrupts normal operation of Apache Tomcat servers running affected versions.
Mitigation Recommendations
A patch is available. Users should upgrade to Apache Tomcat versions 9.0.104, 10.1.40, or 11.0.6 or later to remediate this vulnerability. No other mitigation actions are specified or required.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- BIT-tomcat-2025-31650
- Osv Schema Version
- 1.6.2
- Aliases
- CVE-2025-31650
- Ecosystems
- Bitnami
- Database Specific Severity
- High
Threat ID: 6aa005b8acd9273b49ab59e4
Added to database: 09/08/2026, 12:55:20 UTC
Last enriched: 09/08/2026, 13:13:02 UTC
Last updated: 10/24/2026, 08:45:08 UTC
Views: 52
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