Brute Force Vulnerability in Ruby JSON Web Encryption Implementation by JWT
CVE-2025-54887

9.1CRITICAL

Key Information:

Vendor

Jwt

Status
Ruby-jwe
Vendor
CVE Published:
8 August 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-54887?

The jwe library, which implements the JSON Web Encryption standard for Ruby, has a vulnerability in versions 1.1.0 and earlier that allows an attacker to brute force authentication tags of encrypted JSON Web Encryptions (JWEs). This vulnerability threatens the confidentiality of sensitive data contained in JWEs, enabling attackers to manipulate or craft arbitrary JWEs. Even users not employing the AES-GCM encryption algorithm are at risk due to potential exposure of the GCM internal GHASH key. It is essential for users to rotate their encryption keys following an upgrade to version 1.1.1, where this issue has been resolved.

Affected Version(s)

ruby-jwe < 1.1.1

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

PoC_CVE-2025-54887
Created by shinigami-777

References

https://github.com/jwt/ruby-jwe/security/advisories/GHSA-...
x_refsource_CONFIRM
https://github.com/jwt/ruby-jwe/commit/1e719d79ba3d7aadaa...
x_refsource_MISC

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2025-54887 : Brute Force Vulnerability in Ruby JSON Web Encryption Implementation by JWT