Vulnerability Monitor

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CVE-2021-46743


In Firebase PHP-JWT before 6.0.0, an algorithm-confusion issue (e.g., RS256 / HS256) exists via the kid (aka Key ID) header, when multiple types of keys are loaded in a key ring. This allows an attacker to forge tokens that validate under the incorrect key. NOTE: this provides a straightforward way to use the PHP-JWT library unsafely, but might not be considered a vulnerability in the library itself.


Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.1, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), for affected systems. Impacting 1 product from google organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2022, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2022-03-29T07:15:07.017

Last Modified

2024-11-21T06:34:37.197

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 9.1 (CRITICAL)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:P/I:P/A:N

  • Access Vector: NETWORK
  • Access Complexity: MEDIUM
  • Authentication: NONE
  • Confidentiality Impact: PARTIAL
  • Integrity Impact: PARTIAL
  • Availability Impact: NONE
Exploitability Score

8.6

Impact Score

4.9

Weaknesses
  • Type: Primary
    CWE-843

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application google firebase_php-jwt < 6.0.0 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For google's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.