CVE-2026-59876protobufjs compiles protobuf definitions into JavaScript (JS) functions.
Updated under an hour ago ()
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It affects protobufjs_project protobufjs. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 until 8.6.5, the protobufjs Text Format extension parsed string-keyed map entries using ordinary property assignment, allowing a map entry with key __proto__ to change the prototype of the returned map object instead of creating an own map entry in protobufjs/ext/textformat. This issue is fixed in version 8.6.5.
- CVSS
- 4.8 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
- Weakness (CWE)
- CWE-1321
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jul 13, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
protobufjs_project protobufjs protobufjs_project:protobufjs | from 8.2.0 before 8.6.5 | NVD |
References
- https://github.com/protobufjs/protobuf.js/commit/9f97fe413072d3beb52c74e62d88ea8adc9444d8patch
- https://github.com/protobufjs/protobuf.js/pull/2335issue-tracking, patch
- https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.5product, release-notes
- https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jfj6-75fj-8934mitigation, vendor-advisory
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.