# CVE-2025-4565: PYSEC-2026-1806 - protobuf-python has a potential Denial of Service issue

Source: https://junglewise.ai/threats/cve-2025-4565-protobuf-python-has-a-potential-denial-of-service-issue  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-07  
License: CC BY 4.0 with a link back

CVE-2025-4565 · Severity: medium · CVSS 4 · Published 2026-07-07

protobuf-python has a potential Denial of Service issue

Technologies: [protobuf (PyPI)](https://junglewise.ai/threats/technologies/pypi-protobuf). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2025-4565 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-4565 being exploited in the wild.

**How severe is CVE-2025-4565?** Medium severity, with a CVSS score of 4, published 7 July 2026.

**Which products and versions are affected?** protobuf (PyPI) ECOSYSTEM:introduced=0,fixed=4.25.8, ECOSYSTEM:introduced=0,fixed=4.25.8,introduced=5.26.0rc1,fixed=5.29.5,introduced=6.30.0rc1,fixed=6.31.1.

**Is there a fix for CVE-2025-4565?** Yes. protobuf (PyPI): upgrade to 4.25.8, 6.31.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2025-4565?** Check whether you run protobuf (PyPI) 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.

## How to fix

- protobuf (PyPI): upgrade to 4.25.8, 6.31.1 or later

  ```sh
  pip install "protobuf>=6.31.1"
  ```


## Affected products

- protobuf (PyPI) ECOSYSTEM:introduced=0,fixed=4.25.8, ECOSYSTEM:introduced=0,fixed=4.25.8,introduced=5.26.0rc1,fixed=5.29.5,introduced=6.30.0rc1,fixed=6.31.1

## Identifiers

- CVE-2025-4565
- GHSA-8qvm-5x2c-j2w7
- PYSEC-2026-1806

## Related threats

- [PYSEC-2026-899 - protobuf-cpp and protobuf-python have potential Denial of Service issue](https://junglewise.ai/threats/cve-2022-1941-protobuf-cpp-and-protobuf-python-have-potential-denial-of-service)
- [Google Protobuf denial of service in Python json_format.ParseDict](https://junglewise.ai/threats/cve-2026-0994-google-protobuf-denial-of-service-in-python-json-format-parsedict)
- [Google Protobuf heap buffer overflow](https://junglewise.ai/threats/cve-2015-5237-google-protobuf-heap-buffer-overflow)
- [Withdrawn Advisory: NULL Pointer Dereference in Protocol Buffers](https://junglewise.ai/threats/cve-2021-22570-withdrawn-advisory-null-pointer-dereference-in-protocol-buffers)