CVE-2026-45740 protobufjs: Denial of Service via unbounded recursive JSON descriptor expansion
Attackers can cause denial of service in applications using protobufjs by supplying deeply nested JSON descriptors that exhaust the call stack.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-45740?
CVE-2026-45740 is a medium-severity denial of service 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 7.5.8 and 8.2.0, protobufjs could recurse without a depth limit while expanding nested JSON descriptors through Root.fromJSON() and Namespace.addJSON(). A crafted JSON descriptor with deeply nested namespace definitions could cause the JavaScript call stack to be exhausted during descriptor loading. This vulnerability is fixed in 7.5.8 and 8.2.0.
Weakness: CWE-674
Which versions are affected by CVE-2026-45740?
4 open source packages ship an affected version, including protobufjs. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
protobufjs npm | All versions | 7.5.8 |
protobufjs npm | All versions | 7.5.8 |
protobufjs npm | From 8.0.0 | 8.2.0 |
protobufjs npm | From 8.0.0 | 8.2.0 |
Products include Protobufjs Project Protobufjs.
How do I fix CVE-2026-45740?
Upgrade protobufjs to a fixed version for your release line: 7.5.8 or 8.2.0.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-45740 being exploited?
There is no known exploitation of CVE-2026-45740 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-AZ83054, CLEANSTART-2026-RU46318, ECHO-5c56-1b39-01b7, GHSA-jggg-4jg4-v7c6, MINI-2wv4-prc5-87pw, MINI-3pff-62pv-rvr5 and 15 more.