Vulnerability Description
protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 to 8.4.2, protobufjs preserved unknown wire elements in message.$unknowns and did not provide a decode-time option to discard unknown fields before retaining them. A crafted protobuf payload containing many unknown fields could therefore cause a decoded message to retain substantially more memory than the input size would suggest, even when unknown-field round-tripping is not needed. protobufjs 8.5.0 added the relevant decode-time options, allowing applications that decode untrusted protobuf data to disable unknown-field retention during decode. protobufjs 8.6.2 flips the default so unknown fields are discarded unless explicitly opted into.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Protobufjs Project | Protobufjs | >= 8.2.0, < 8.5.0 |
Related Weaknesses (CWE)
References
- https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-94rc-8x27-447MitigationVendor Advisory
FAQ
What is CVE-2026-54270?
CVE-2026-54270 is a vulnerability with a CVSS score of 5.3 (MEDIUM). protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 to 8.4.2, protobufjs preserved unknown wire elements in message.$unknowns and did not provide a decode-time option t...
How severe is CVE-2026-54270?
CVE-2026-54270 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-54270?
Check the references section above for vendor advisories and patch information. Affected products include: Protobufjs Project Protobufjs.