RCE in Protobufjs Protobuf.js

CVE-2026-41242

protobufjs compiles protobuf definitions into JavaScript (JS) functions. In versions prior to 8.0.1 and 7.5.5, attackers can inject arbitrary code in the "type" fields of protobuf definitions, which will then execute during object decoding using that definition. Versions 8.0.1 and 7.5.5 patch the issue.

Vulnerability class: RCE (Remote Code Execution)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.010 (61.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-41242: held from 0.007 to 0.010.

EPSS over last 30 days · oldest: 0.007 · newest: 0.010 · change: +0.002

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-41242?
CVE-2026-41242 is a critical-severity vulnerability in Protobufjs Protobuf.js, classified under Code Injection. CVSS score: 9.8/10. Published 2026-04-18.
How severe is CVE-2026-41242?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-41242 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.