Vulnerability · Published Apr 15, 2026 · Assigned by certcc
CVE-2026-5758Mafintosh's protocol-buffers-schema is vulnerable to prototype pollution
Medium 6.5
In plain English
A medium-severity security flaw in Protocol-buffers-schema parser from Mafintosh. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.5%top 54.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | protocol-buffers-schema | 3.6.1 | GHSA-j452-xhg8-qg39 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mafintosh | Protocol-buffers-schema parser | 3.6.0 – before 3.6.1 |