CVE-2026-59877

MEDIUM 5.3

protobufjs: Denial of Service via infinite loop in .proto option parsing

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.5 and 8.6.6, protobufjs parsed option names by advancing through schema tokens until reaching an = token without checking for end of input, so a crafted .proto schema that opens an option declaration and ends prematurely can cause parse, Root.load, or Root.loadSync to loop indefinitely. This issue is fixed in versions 7.6.5 and 8.6.6.

CWE	CWE-835
Vendor	protobufjs
Product	protobuf.js
Published	Jul 8, 2026
Last Updated	Jul 8, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Affected Versions

protobufjs / protobuf.js

>= 7.5.0, < 7.6.5 >= 8.0.0, < 8.6.6

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-j3f2-48v5-ccww github.com: https://github.com/protobufjs/protobuf.js/pull/2352 github.com: https://github.com/protobufjs/protobuf.js/commit/10fba6d54815ceecca8a06b9a6db490c8f5d2217 github.com: https://github.com/protobufjs/protobuf.js/commit/fa5c73add738ceb471e74da8cc2f3727c3d0a69f github.com: https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v7.6.5 github.com: https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.6