CVE-2026-44293 protobufjs: Code injection through bytes field defaults in generated toObject code
Attackers can execute arbitrary code by crafting a protobuf descriptor with a malicious bytes field default value in protobufjs.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44293?
CVE-2026-44293 is a high-severity code injection vulnerability in protobufjs protobuf.js, published on 13 May 2026. Any signed-in user can exploit it over the network, 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 JavaScript for toObject conversion could include an unsafe expression derived from a schema-controlled bytes field default value. A crafted descriptor with a non-string default value for a bytes field could cause attacker-controlled code to be emitted into the generated conversion function. This vulnerability is fixed in 7.5.6 and 8.0.2.
Weakness: CWE-94
Which versions are affected by CVE-2026-44293?
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-2026-44293?
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-2026-44293 being exploited?
There is no known exploitation of CVE-2026-44293 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-2026-48712 protobufjs: Denial of service through unbounded Any expansion during JSON conversion
Sources
Also known as CLEANSTART-2026-AV38227, CLEANSTART-2026-CY64651, CLEANSTART-2026-XF24376, ECHO-0641-6a07-e4b8, GHSA-66ff-xgx4-vchm, MINI-2996-px72-grmg and 16 more.