Medium 5.3Published Jul 8, 2026

CVE-2026-59877protobufjs: Denial of Service via infinite loop in .proto option parsing

Updated under an hour ago (Oct 27, 2026, 10:23 AM ET)

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It affects protobufjs protobuf.js and 1 other product. Add what you run to find out whether that includes you.

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Every CVE for protobufjs protobuf.js

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-835
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 8, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

protobufjs protobuf.js protobufjs:protobuf.js (from the name)	from 7.5.0, < 7.6.5; from 8.0.0, < 8.6.6	CNA record
protobufjs_project protobufjs protobufjs_project:protobufjs	before 7.6.5; from 8.0.0 before 8.6.6	NVD

References

References

https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-j3f2-48v5-ccww	x-refsource-confirm, mitigation, vendor-advisory
https://github.com/protobufjs/protobuf.js/pull/2352	x-refsource-misc, issue-tracking, patch
https://github.com/protobufjs/protobuf.js/commit/10fba6d54815ceecca8a06b9a6db490c8f5d2217	x-refsource-misc, patch
https://github.com/protobufjs/protobuf.js/commit/fa5c73add738ceb471e74da8cc2f3727c3d0a69f	x-refsource-misc, patch
https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v7.6.5	x-refsource-misc, product, release-notes
https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.6	x-refsource-misc, product, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.