CVE-2026-56091 Apache Shiro: Authentication bypass in Guice-Web integration
Attackers can bypass authentication in Apache Shiro web applications using the shiro-guice module via crafted HTTP requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56091?
CVE-2026-56091 is a high-severity authentication bypass vulnerability in Apache Shiro, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
When using Apache Shiro with the shiro-guice module in a web servlet context, a specially crafted HTTP request may cause an authentication bypass. This vulnerability is similar to https://www.cve.org/CVERecord?id=CVE-2020-1957 https://www.cve.org/CVERecord , except that it affects the `shiro-guice` module instead of the `shiro-spring` module.
This issue affects all Apache Shiro versions through 2.x, and 3.0.0-alpha-1 only when using `shiro-guice` module in a web servlet context.
Upgrade to version 3.0.0 or later, which fixes the issue.
Weakness: CWE-289
Which versions are affected by CVE-2026-56091?
How do I fix CVE-2026-56091?
No fix has been published for CVE-2026-56091 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-56091 being exploited?
There is no known exploitation of CVE-2026-56091 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-56091, GHSA-qj64-jj84-w38j, UBUNTU-CVE-2026-56091.