Quick answers
- Is CVE-2026-14539 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-14539 being exploited in the wild.
- How severe is CVE-2026-14539?
- Informational severity, with a CVSS score of 6.6, published 31 July 2026.
- Which products and versions are affected?
- Google MCP Toolbox up to and including 1.4.0.
- Is there a fix for CVE-2026-14539?
- A patch was published on 2026-05-12: Fix submitted via Pull Request #3216 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-14539 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-14539?
- Check whether you run Google MCP Toolbox at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in the /mcp endpoint handler of Google mcp-toolbox due to the use of an unrestricted buffer loop (io.ReadAll) when reading incoming HTTP payloads. The component fails to implement defensive constraints such as http.MaxBytesReader or Content-Length enforcement. A remote, unauthenticated attacker can exploit this by submitting a massive HTTP request body, leading to linear memory consumption and an eventual Out-Of-Memory (OOM) termination of the process. The issue is addressed in pull request #3216 by implementing a 10 MiB limit using http.MaxBytesReader.
Affected products
- Google mcp-toolbox up to and including 1.4.0
Timeline
- 2026-05-12: patched: Fix submitted via Pull Request #3216
- 2026-07-31: advisory: NVD publication date