Bugsink: DOS using large numbers of event tags

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

4.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-53954: 0.56% estimated exploitation activity in the next 30 days; percentile 46.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary In affected versions, Bugsink stores every tag supplied with an incoming event. An event with an unusually large number of custom (i.e. supplied by an attacker) tags can therefore make ingestion spend more time than intended writing tag rows. Bugsink uses a single-writer database architecture. That keeps the implementation simple, but it also means one expensive write transaction can delay other event digestion while it is running. In this case, it makes ingestion of other events wait until the transaction that writes the tags finishes, which effectively causes a temporary denial of service for other events. Impact Submitting such an event requires a valid project DSN. DSNs are sometimes visible in client-side applications, so they should not be treated as a strong security boundary, but the issue is still limited to ingestion for a Bugsink instance that accepts the event. The impact is availability-only. The issue does not expose stored data, modify existing events, or allow…

Published by the source

5 Jun 2026, 21:45 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:45 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5x67-j5xg-c5gj

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5x67-j5xg-c5gj

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# Patch Next advisory brief: CVE-2026-53954

Advisory: Bugsink: DOS using large numbers of event tags
IDs: CVE-2026-53954, GHSA-5x67-j5xg-c5gj
Record: https://patchnext.com/advisories/cve-2026-53954 (revision 2, source checked 26 Oct 2026, 13:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: bugsink 2.2.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI bugsink: affected <= 2.2.1; fixed in 2.2.2

## Suggested inspection (read-only)
- `python -m pip show bugsink`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on bugsink.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5x67-j5xg-c5gj (OSV record GHSA-5x67-j5xg-c5gj lists affected ranges: PyPI bugsink >=0 <2.2.2 (fixed))
- Verified: https://github.com/advisories/GHSA-5x67-j5xg-c5gj (GitHub-reviewed advisory GHSA-5x67-j5xg-c5gj lists affected ranges: PyPI bugsink >=0 <=2.2.1)

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