---
id: CVE-2025-64509
aliases:
  - GHSA-rrx3-2x4g-mq2h
  - PYSEC-2026-1227
title: >-
  Bugsink is vulnerable to unauthenticated remote DoS via crafted Brotli input
  (via CPU)
summary: >-
  Bugsink is vulnerable to unauthenticated remote DoS via crafted Brotli input
  (via CPU)
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: bugsink
product: bugsink
ecosystem: pip
affected:
  - bugsink < 2.0.6
patched:
  - bugsink 2.0.6
published: '2025-11-13'
updated: '2026-07-07'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-rrx3-2x4g-mq2h'
references:
  - url: 'https://github.com/bugsink/bugsink/security/advisories/GHSA-rrx3-2x4g-mq2h'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-64509'
  - url: >-
      https://github.com/bugsink/bugsink/commit/1201f754e39265d2aac58edf49dc380bac334388
  - url: 'https://github.com/bugsink/bugsink'
tags:
  - osv
  - pip
epss: 0.00315
epssPercentile: 0.21694
ingestedAt: '2026-07-08T18:25:53.021Z'
---

## Overview

### Impact

In affected versions, a specially crafted Brotli-compressed envelope can cause Bugsink to spend excessive CPU time in decompression, leading to denial of service.

This can be done if the DSN is known, which it is in many common setups (JavaScript, Mobile Apps).

### Patches

Patched in Bugsink 2.0.6

### References

The vulnerability in this security advisory is similar to, but distinct from, another brotli-related problem in Bugsink:

https://github.com/bugsink/bugsink/security/advisories/GHSA-fc2v-vcwj-269v

## Affected packages

- `bugsink < 2.0.6`

## Remediation

Upgrade to a patched release:

- `bugsink 2.0.6`