PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-41242 protobufjs CVE debrief

CVE-2026-41242 is a critical vulnerability in protobufjs, a JavaScript library for working with Protocol Buffers. The vulnerability allows attackers to inject arbitrary code in the 'type' fields of protobuf definitions, which can then be executed during object decoding. This issue affects versions prior to 8.0.1 and 7.5.5. The vulnerability has a CVSS score of 9.4 and is considered critical. Protobufjs Project has released patches for this issue.

Vendor
protobufjs
Product
protobuf.js
CVSS
CRITICAL 9.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-18
Original CVE updated
2026-09-09
Advisory published
2026-04-18
Advisory updated
2026-09-09

Who should care

Developers and organizations using protobufjs in their applications should be aware of this vulnerability and take steps to mitigate it. This includes upgrading to versions 8.0.1 or 7.5.5, or applying patches provided by the vendor. Additionally, users of Red Hat products may be affected, as indicated by the presence of Red Hat errata references.

Technical summary

The vulnerability in protobufjs allows for code injection through the 'type' fields of protobuf definitions. This can occur when an attacker can manipulate the protobuf definition used for decoding objects. The issue is due to insufficient validation of user input in the protobufjs library. The CVSS vector for this vulnerability is CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

Defensive priority

This vulnerability has a high defensive priority due to its critical CVSS score and potential for code execution. Immediate action should be taken to mitigate this vulnerability.

Recommended defensive actions

  • Upgrade to protobufjs version 8.0.1 or 7.5.5
  • Apply patches provided by the vendor
  • Review and update affected Red Hat products using the provided errata references
  • Validate and sanitize user input to protobuf definitions
  • Monitor for suspicious activity related to protobuf usage

Evidence notes

The CVE-2026-41242 vulnerability was publicly disclosed on April 18, 2026, and has since been modified on June 30, 2026. The vulnerability affects protobufjs versions prior to 8.0.1 and 7.5.5. Multiple sources, including NVD and Red Hat, have documented this vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-41242 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-41242

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-41242 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-41242

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.