CVE-2023-34981

A regression in the fix for bug 66512 in Apache Tomcat 11.0.0-M5, 10.1.8, 9.0.74 and 8.5.88 meant that, if a response did not include any HTTP headers no AJP SEND_HEADERS message would be sent for the response which in turn meant that at least one AJP proxy (mod_proxy_ajp) would use the response headers from the previous request leading to an information leak.

A file, directory, or other resource is assigned permissions that allow broader access than intended. Typical impact: unauthorized read, modification, or execution of the resource.

CVE-2023-34981 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (11.0.0-M6, 10.1.9, 9.0.75, 8.5.89); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2023-34981? CVE-2023-34981 is a high-severity incorrect permission assignment for critical resource vulnerability in org.apache.tomcat.embed:tomcat-embed-core (maven), affecting versions = 11.0.0-M5. It is fixed in 11.0.0-M6, 10.1.9, 9.0.75, 8.5.89. A file, directory, or other resource is assigned permissions that allow broader access than intended.
2. How severe is CVE-2023-34981? CVE-2023-34981 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2023-34981?
   • org.apache.tomcat.embed:tomcat-embed-core (maven) (versions = 11.0.0-M5)
   • org.apache.tomcat:tomcat-coyote (maven) (versions = 8.5.88)
4. Is there a fix for CVE-2023-34981? Yes. CVE-2023-34981 is fixed in 11.0.0-M6, 10.1.9, 9.0.75, 8.5.89. Upgrade to this version or later.
5. Is CVE-2023-34981 exploitable, and should I be worried? Whether CVE-2023-34981 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-34981 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-34981?
   • Upgrade org.apache.tomcat.embed:tomcat-embed-core to 11.0.0-M6 or later
   • Upgrade org.apache.tomcat.embed:tomcat-embed-core to 10.1.9 or later
   • Upgrade org.apache.tomcat.embed:tomcat-embed-core to 9.0.75 or later
   • Upgrade org.apache.tomcat:tomcat-coyote to 8.5.89 or later