CVE-2025-64509: Bugsink Denial of Service Vulnerability

HIGH
Advisory Identifier: GHSA-rrx3-2x4g-mq2h
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CVSS 7.5
CWE-770
Published
Advisory Summary

CVE-2025-64509 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Bugsink libraries in the PyPI ecosystem. The issue involves bugsink is vulnerable to unauthenticated remote dos via crafted brotli input (via cpu). Remediation is available by upgrading affected packages to version 2.0.6.

CVE-2025-64509 at a Glance

CVE Identifier CVE-2025-64509
GHSA Identifier GHSA-rrx3-2x4g-mq2h
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Bugsink
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2025-64509

To remediate this vulnerability, upgrade all affected Bugsink dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

bugsink fixed: 2.0.6 
pip install bugsink>=2.0.6
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show bugsink

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-64509, inspect your installed packages using pip:

pip show bugsink

Analyze the terminal output to locate any version of Bugsink in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.0.6), your application is affected.

Note: The pip show bugsink command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Bugsink, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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

CVE-2025-64509 Affected Bugsink Versions

1 component(s)
Fixed Versions:
2.0.6
Product / Package Ecosystem Affected Versions Fixed Version
bugsink
pypi/bugsink
PyPI
< 2.0.6
2.0.6

References

GitHub Advisory / Wiki ADVISORY
https://github.com/bugsink/bugsink/security/advisories/GHSA-rrx3-2x4g-mq2h
NVD — CVE-2025-64509 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-64509
Security Fix Commit FIX COMMIT
https://github.com/bugsink/bugsink/commit/1201f754e39265d2aac58edf49dc380bac334388
Bugsink Source Repository REPOSITORY
https://github.com/bugsink/bugsink

Frequently Asked Questions

What is CVE-2025-64509?
CVE-2025-64509 is a security vulnerability in Bugsink involving Bugsink is vulnerable to unauthenticated remote DoS via crafted Brotli input (via CPU) under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Bugsink versions are affected?
Affected versions include releases prior to 2.0.6 across affected packages: bugsink.
What version fixes CVE-2025-64509?
Upgrading to 2.0.6 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bugsink affected?
Yes, bugsink is affected in releases prior to 2.0.6. Upgrade your dependency to 2.0.6 or later.
What is the CVSS score of CVE-2025-64509?
CVE-2025-64509 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2025-64509?
CVE-2025-64509 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check PyPI dependencies for CVE-2025-64509?
Run the dependency tree command: 'pip show bugsink'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rrx3-2x4g-mq2h",
  "modified" : "2025-11-13T00:11:27Z",
  "published" : "2025-11-13T00:11:26Z",
  "aliases" : [ "CVE-2025-64509" ],
  "summary" : "Bugsink is vulnerable to unauthenticated remote DoS via crafted Brotli input (via CPU)",
  "details" : "### Impact\n\nIn affected versions, a specially crafted Brotli-compressed envelope can cause Bugsink to spend excessive CPU time in decompression, leading to denial of service.\n\nThis can be done if the DSN is known, which it is in many common setups (JavaScript, Mobile Apps).\n\n### Patches\n\nPatched in Bugsink 2.0.6\n\n### References\n\nThe vulnerability in this security advisory is similar to, but distinct from, another brotli-related problem in Bugsink:\n\nhttps://github.com/bugsink/bugsink/security/advisories/GHSA-fc2v-vcwj-269v",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "bugsink"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.0.6"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/bugsink/bugsink/security/advisories/GHSA-rrx3-2x4g-mq2h"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-64509"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/bugsink/bugsink/commit/1201f754e39265d2aac58edf49dc380bac334388"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/bugsink/bugsink"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-11-13T00:11:26Z",
    "nvd_published_at" : "2025-11-10T22:15:39Z"
  }
}