# CVE-2026-41293: Apache Tomcat improper input validation in HTTP/2 request headers

Source: https://junglewise.ai/threats/cve-2026-41293-apache-tomcat-improper-input-validation-in-http-2-request-headers  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-12. Updated: 2026-05-18  
License: CC BY 4.0 with a link back

CVE-2026-41293 · Severity: critical · CVSS 9.8 · Published 2026-05-12

Apache Tomcat is a widely used web server and application container for Java-based software. A vulnerability in its handling of HTTP/2 web traffic could allow attackers to send specially crafted request headers that bypass standard security checks. This may lead to unexpected application behavior, potentially allowing unauthorized access to data or disruption of services depending on how the hosted application processes these headers.

Technologies: [Apache Tomcat](https://junglewise.ai/threats/technologies/tomcat), [org.apache.tomcat:tomcat (Maven)](https://junglewise.ai/threats/technologies/org-apache-tomcat-tomcat), [org.apache.tomcat:tomcat-coyote (Maven)](https://junglewise.ai/threats/technologies/org-apache-tomcat-tomcat-coyote), [org.apache.tomcat.embed:tomcat-embed-core (Maven)](https://junglewise.ai/threats/technologies/org-apache-tomcat-embed-tomcat-embed-core). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache), [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-41293 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41293 being exploited in the wild.

**How severe is CVE-2026-41293?** Critical severity, with a CVSS score of 9.8, published 12 May 2026.

**Which products and versions are affected?** Apache Tomcat 11.0.0-M1 to 11.0.21, 10.1.0-M1 to 10.1.54, 9.0.0.M1 to 9.0.117, 10.0.0-M1 to 10.0.27, 8.5.0 to 8.5.100; org.apache.tomcat:tomcat (Maven) ECOSYSTEM:introduced=8.5.0,fixed=9.0.118; org.apache.tomcat:tomcat-coyote (Maven) ECOSYSTEM:introduced=8.5.0,fixed=9.0.118; org.apache.tomcat.embed:tomcat-embed-core (Maven) ECOSYSTEM:introduced=8.5.0,fixed=9.0.118.

**Is there a fix for CVE-2026-41293?** Yes. org.apache.tomcat:tomcat (Maven): upgrade to 9.0.118 or later; org.apache.tomcat:tomcat-coyote (Maven): upgrade to 9.0.118 or later; org.apache.tomcat.embed:tomcat-embed-core (Maven): upgrade to 9.0.118 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-41293 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-41293?** Check whether you run Apache Tomcat, org.apache.tomcat:tomcat (Maven), org.apache.tomcat:tomcat-coyote (Maven) or one of the others listed 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.

## How to fix

- org.apache.tomcat:tomcat (Maven): upgrade to 9.0.118 or later

  ```sh
  # set org.apache.tomcat:tomcat to 9.0.118 in your pom.xml or build.gradle
  ```

- org.apache.tomcat:tomcat-coyote (Maven): upgrade to 9.0.118 or later

  ```sh
  # set org.apache.tomcat:tomcat-coyote to 9.0.118 in your pom.xml or build.gradle
  ```

- org.apache.tomcat.embed:tomcat-embed-core (Maven): upgrade to 9.0.118 or later

  ```sh
  # set org.apache.tomcat.embed:tomcat-embed-core to 9.0.118 in your pom.xml or build.gradle
  ```


## Technical details

An improper input validation vulnerability exists in Apache Tomcat's HTTP/2 implementation. The server fails to validate HTTP/2 request headers against specifications before exposing them to applications through the Servlet API. If an application assumes these headers are specification-compliant, an attacker can trigger unexpected logic or security bypasses by providing malformed header values. The vulnerability is reachable over the network without authentication. Fixes have been released in versions 11.0.22, 10.1.55, and 9.0.118, which introduce header filtering to align HTTP/2 behavior with HTTP/1.1.

## Affected products

- Apache Tomcat 11.0.0-M1 to 11.0.21, 10.1.0-M1 to 10.1.54, 9.0.0.M1 to 9.0.117, 10.0.0-M1 to 10.0.27, 8.5.0 to 8.5.100

## Identifiers

- CVE-2026-41293
- GHSA-r29c-68gh-xp6x

## Timeline

- 2026-05-12: disclosed
- 2026-05-12: advisory

## References

- [https://lists.apache.org/thread/qwg0q16z7xkb2qrr853wdll5531mvl1r](https://lists.apache.org/thread/qwg0q16z7xkb2qrr853wdll5531mvl1r)
- [http://www.openwall.com/lists/oss-security/2026/05/12/13](http://www.openwall.com/lists/oss-security/2026/05/12/13)
- [https://github.com/apache/tomcat/commit/19f17a257797e8d139b33ff9c88d362a273be148](https://github.com/apache/tomcat/commit/19f17a257797e8d139b33ff9c88d362a273be148)
- [https://github.com/apache/tomcat/commit/1c70480466572c9192ed412ebefcd43fc63137fd](https://github.com/apache/tomcat/commit/1c70480466572c9192ed412ebefcd43fc63137fd)
- [https://github.com/apache/tomcat/commit/2a2476460e823789f530a22207873ea8cd6eff3b](https://github.com/apache/tomcat/commit/2a2476460e823789f530a22207873ea8cd6eff3b)

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