CVE-2026-56091
Auth bypass in Apache Shiro shiro-guice module in web apps.
Is CVE-2026-56091 being exploited?
Not confirmed. CVE-2026-56091 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.67% probability of exploitation in the next 30 days.
How severe is CVE-2026-56091?
CVE-2026-56091 is rated High with a CVSS score of 8.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-56091?
Yes. A fix has been recorded for CVE-2026-56091. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-56091 affect?
CVE-2026-56091 affects Apache Shiro with shiro-guice module (all 2.x; 3.0.0-alpha-1 with guice). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-56091?
Upgrade to Shiro 3.0.0+; audit guice usage; deploy patch.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Auth bypass via crafted HTTP requests in shiro-guice-enabled web apps, enabling access to protected resources.
Patch when possible
- affected<= 2.99.99
- affected>= 3.0.0-alpha-0 and <= 3.0.0-alpha-1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.