What’s Vulnerable › Vulnerabilities

CVE-2026-75627: Bastillion Authentication Bypass via Path-Prefix Routing Mismatch

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-18 · updated 2026-10-22
• Weakness: CWE-288

Description

Bastillion fails to properly validate request URI paths in its controller dispatcher, allowing unauthenticated attackers to bypass authentication filters by prefixing requests with arbitrary path segments. Attackers can access administrative controllers to read user listings, create manager accounts, and register managed systems, gaining control over SSH access to the managed fleet.

Affected products

• bastillion-io Bastillion: through 5.1.0

References

• https://github.com/bastillion-io/Bastillion
• https://github.com/bastillion-io/Bastillion/blob/master/src/main/java/loophole/mvc/base/BaseKontroller.java
• https://github.com/bastillion-io/Bastillion/commit/d759fb686a1a097b1b026e286fd9b20e5ba349c8
• https://github.com/bastillion-io/Bastillion/issues/669
• https://www.vulncheck.com/advisories/bastillion-authentication-bypass-via-path-prefix-routing-mismatch
• https://github.com/bastillion-io/Bastillion/issues/669

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