# CVE-2026-53954: Bugsink denial of service via excessive event tags

Source: https://junglewise.ai/threats/cve-2026-53954-bugsink-denial-of-service-via-excessive-event-tags  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-53954 · Severity: medium · CVSS 4.3 · Published 2026-09-15

Bugsink is a self-hosted error tracking platform used by development teams to capture and analyze application errors. Prior to version 2.2.2, an attacker with a valid project DSN credential could submit events containing an unusually large number of custom tags, forcing excessive database writes that delay processing of legitimate events and cause temporary service unavailability for the affected instance.

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

## Quick answers

**Is CVE-2026-53954 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-53954 being exploited in the wild.

**How severe is CVE-2026-53954?** Medium severity, with a CVSS score of 4.3, published 15 September 2026.

**Which products and versions are affected?** Bugsink before 2.2.2; bugsink (PyPI) ECOSYSTEM:introduced=0,fixed=2.2.2.

**Is there a fix for CVE-2026-53954?** Yes. bugsink (PyPI): upgrade to 2.2.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-53954 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-53954?** Check whether you run Bugsink or bugsink (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

- bugsink (PyPI): upgrade to 2.2.2 or later

  ```sh
  pip install "bugsink>=2.2.2"
  ```


## Technical details

This is a denial-of-service vulnerability in Bugsink's event ingestion pipeline. The vulnerability stems from unbounded tag storage: the application accepted and stored any number of custom tags supplied with incoming events without validation. An authenticated attacker (requiring a valid project DSN) could exploit this by crafting requests with extremely large tag sets, causing expensive single-writer database transactions that block digestion of other events. The fix in version 2.2.2 introduces a configurable MAX_EVENT_TAGS limit (default 1000) enforced before storage. The vulnerability is network-reachable but requires valid DSN credentials; impact is limited to availability with no data exposure, modification, or code execution.

## Affected products

- Bugsink Bugsink before 2.2.2

## Identifiers

- CVE-2026-53954
- GHSA-5x67-j5xg-c5gj
- PYSEC-2026-2403

## Timeline

- 2026-09-15: disclosed
- 2026-09-15: patched: Fixed in version 2.2.2

## References

- [https://github.com/bugsink/bugsink/commit/1d0539fefcd1a796143d15d84053b1c0122ef8c7](https://github.com/bugsink/bugsink/commit/1d0539fefcd1a796143d15d84053b1c0122ef8c7)
- [https://github.com/bugsink/bugsink/commit/8dca571b9e66c535ed4885465db820824e7c491a](https://github.com/bugsink/bugsink/commit/8dca571b9e66c535ed4885465db820824e7c491a)

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- [PYSEC-2026-1225 - Bugsink is vulnerable to unauthenticated remote DoS via crafted Brotli input](https://junglewise.ai/threats/cve-2025-64508-bugsink-is-vulnerable-to-unauthenticated-remote-dos-via-crafted)
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