What’s Vulnerable › Vulnerabilities

CVE-2026-5758: Mafintosh's protocol-buffers-schema is vulnerable to prototype pollution

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-15 · updated 2026-10-26

Description

JavaScript is vulnerable to prototype pollution in Mafintosh's protocol-buffers-schema Version 3.6.0, where an attacker may alter the application logic, bypass security checks, cause a DoS or achieve remote code execution.

Affected products

• Mafintosh Protocol-buffers-schema parser: from 3.6.0 before 3.6.1 — fixed in 3.6.1

How to fix

Upgrade to a fixed version: Mafintosh Protocol-buffers-schema parser 3.6.1. Check the vendor advisory for mitigations.

References

• https://github.com/mafintosh/protocol-buffers-schema/pull/70
• https://morielharush.github.io/2026/04/12/cve-2026-5758-protocol-buffers-schema-prototype-pollution/

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