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Signature Verification Bypass in jwt-simple

high severity Published Jun 6, 2019 • Updated Aug 4, 2021

Package

npm jwt-simple (npm)

Affected versions

< 0.5.3

Patched versions

0.5.3

Description

Versions of jwt-simple prior to 0.5.3 are vulnerable to Signature Verification Bypass. If no algorithm is specified in the decode() function, the packages uses the algorithm in the JWT to decode tokens. This allows an attacker to create a HS256 (symmetric algorithm) JWT with the server's public key as secret, and the package will verify it as HS256 instead of RS256 (asymmetric algorithm).

Recommendation

Upgrade to version 0.5.3 or later.

References

GHSA ID

GHSA-8v5f-hp78-jgxq