CVE-2026-44292 protobufjs: Prototype injection in generated message constructors
Attackers can inject code or escalate privileges by exploiting prototype pollution in protobufjs message constructors via crafted input objects.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44292?
CVE-2026-44292 is a medium-severity code injection vulnerability in protobufjs protobuf.js, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs generated message constructors copied enumerable properties from a provided properties object without filtering the __proto__ key. If an application constructed a message from an attacker-controlled plain object, an own enumerable __proto__ property could alter the prototype of that individual message instance. This vulnerability is fixed in 7.5.6 and 8.0.2.
Weakness: CWE-1321
Which versions are affected by CVE-2026-44292?
4 open source packages ship an affected version, including protobufjs. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
protobufjs npm | All versions | 7.5.6 |
protobufjs npm | All versions | 7.5.6 |
protobufjs npm | From 8.0.0 | 8.0.2 |
protobufjs npm | From 8.0.0 | 8.0.2 |
Products include Protobufjs Project Protobufjs.
How do I fix CVE-2026-44292?
Upgrade protobufjs to a fixed version for your release line: 7.5.6 or 8.0.2.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-44292 being exploited?
There is no known exploitation of CVE-2026-44292 in the wild and no public exploit code.
Other vulnerabilities in protobufjs protobuf.js
- CVE-2023-36665 protobufjs Prototype Pollution vulnerability
- CVE-2026-41242 protobufjs has an arbitrary code execution issue
- CVE-2022-25878 Prototype Pollution
- CVE-2026-44291 protobufjs: Code generation gadget after prototype pollution
- CVE-2026-44293 protobufjs: Code injection through bytes field defaults in generated toObject code
Sources
Also known as CLEANSTART-2026-JC72246, CLEANSTART-2026-SM05133, ECHO-f1f4-d63b-9599, GHSA-fx83-v9x8-x52w, MINI-2qfr-c72r-r42m, MINI-5c33-hvwv-49fr and 15 more.