protobufjs: Text Format string map parsing can mutate returned map object prototype
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| protobufjs | protobuf.js | 8.2.0 to before 8.6.5 | 8.6.5 | Patch available | CNA |
| — | protobufjs (npm) | 8.2.0 to before 8.6.5 | 8.6.5 | Patch available | GHSA-jfj6-75fj-8934 |
- protobuf.js Vendorprotobufjs Affected 8.2.0 to before 8.6.5 Fixed in 8.6.5 Patch available CNA
- protobufjs (npm) Vendor— Affected 8.2.0 to before 8.6.5 Fixed in 8.6.5 Patch available GHSA-jfj6-75fj-8934
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:protobufjs_project:protobufjs:*:*:*:*:*:node.js:*:* | 8.2.0 to before 8.6.5 | Vulnerable | protobufjs |
- cpe:2.3:a:protobufjs_project:protobufjs:*:*:*:*:*:node.js:*:* Versions 8.2.0 to before 8.6.5 Vulnerable ·protobufjs
Remediation
- Fix · CNA protobuf.js (protobufjs) Fixed in 8.6.5
- Fix · GHSA-jfj6-75fj-8934 protobufjs (npm) Fixed in 8.6.5 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Ceph Storage 9 | Affected | No fix yet: Fix deferred |
Not affected: 13 products
- Cryostat 4
- OpenShift Pipelines
- OpenShift Service Mesh 3
- Red Hat Ansible Automation Platform 2
- Red Hat Build of Podman Desktop
- Red Hat Developer Hub 1
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux AI (RHEL AI) 3
- Red Hat Hardened Images
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
- Red Hat Openshift Data Foundation 4
- Self-service automation portal 2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-59876
- 2026-10-03 Alias added: GHSA-jfj6-75fj-8934
- 2026-10-27 Affected versions changed · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
Patch 2
Advisory 2
More Protobufjs vulnerabilities
- TI-2026-29851 protobufjs has an arbitrary code execution issue CVSS 4.0CRITICAL 9.4
- TI-2023-18481 "protobuf.js (aka protobufjs) 6.10.0 through 7.x before 7.2.5 allows Prototype Pollution… CVSS 3.1CRITICAL 9.8
- TI-2026-32260 protobufjs: Denial of service through unbounded protobuf recursion CVSS 3.1HIGH 7.5
- TI-2022-09438 Prototype pollution in protobufjs CVSS 3.1HIGH 8.2
- TI-2026-42691 protobufjs: Denial of Service via infinite loop in .proto option parsing CVSS 3.1HIGH 7.5
- TI-2026-35993 protobufjs: Denial of service through unbounded Any expansion during JSON conversion CVSS 3.1HIGH 7.5
Sources
- CVE-2026-59876 · CVE Program
- CVE-2026-59876 · NVD
- FIRST EPSS
- GHSA-jfj6-75fj-8934 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-59876 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences