CVE-2026-75973 Apache Tomcat: Cross-context authentication mix-up with Jakarta Authentication configured
Attackers can bypass authentication boundaries between web applications using a shared realm, potentially gaining unauthorized access to other contexts.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-75973?
CVE-2026-75973 is a high-severity authentication bypass vulnerability in Apache Tomcat, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper Authentication vulnerability in Apache Tomcat. When Jakarta Authentication was configured with SimpleAuthConfigProvider as the default provider and multiple web application used that provider, the realm for the first web application to authenticate a request would be used for all web applications.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M4 through 9.0.121.
The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100. Other unsupported versions may also be affected.
Users are recommended to upgrade to version 11.0.26, 10.1.60, 9.0.122, which fixes the issue.
Weakness: CWE-287
Which versions are affected by CVE-2026-75973?
1 open source package ship an affected version, including tomcat.
| Package | Affected | Fixed in |
|---|---|---|
tomcat Bitnami | From 8.5.0 | 9.0.45, 10.1.60, 11.0.26, 9.0.122 |
How do I fix CVE-2026-75973?
Upgrade tomcat to a fixed version for your release line: 9.0.45, 10.1.60, 11.0.26 or 9.0.122.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-75973 being exploited?
There is no known exploitation of CVE-2026-75973 in the wild and no public exploit code.
Sources
Also known as BIT-tomcat-2026-75973, DEBIAN-CVE-2026-75973, GHSA-q9fp-9gfr-vj9g, MINI-4r4h-w47g-2cc6, MINI-v2vf-vcch-3638, MINI-x66v-rpm4-rh57 and 1 more.