CVE-2022-31053: Signature forgery in Biscuit

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-06-13 · updated 2026-06-17
Weakness: CWE-347

Description

Biscuit is an authentication and authorization token for microservices architectures. The Biscuit specification version 1 contains a vulnerable algorithm that allows malicious actors to forge valid Γ-signatures. Such an attack would allow an attacker to create a token with any access level. The version 2 of the specification mandates a different algorithm than gamma signatures and as such is not affected by this vulnerability. The Biscuit implementations in Rust, Haskell, Go, Java and Javascript all have published versions following the v2 specification. There are no known workarounds for this issue.

Affected products

biscuit-auth biscuit-rust: from 1.0.0 through 1.1.0
Biscuitsec Biscuit-Go: before 2.0.0 — fixed in 2.0.0
Biscuitsec Biscuit-Haskell: 0.1.1.0
Clever-Cloud Biscuit-Java: before 2.0.0 — fixed in 2.0.0

How to fix

Upgrade to a fixed version: Biscuitsec Biscuit-Go 2.0.0; Clever-Cloud Biscuit-Java 2.0.0. Check the vendor advisory for mitigations.

References

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