cbcvebase.
CVE-2026-40342
published 2026-04-17

CVE-2026-40342: Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, the external engine plugin loader concatenates…

PriorityP267critical9.9CVSS 3.1
AVNACLPRLUINSCCHIHAH
EPSS
0.69%
48.2th percentile
Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, the external engine plugin loader concatenates a user-supplied engine name into a filesystem path without filtering path separators or .. components. An authenticated user with CREATE FUNCTION privileges can use a crafted ENGINE name to load an arbitrary shared library from anywhere on the filesystem via path traversal. The library's initialization code executes immediately during loading, before Firebird validates the module, achieving code execution as the server's OS account. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

Affected

5 ranges
VendorProductVersion rangeFixed in
firebirdsqlfirebird< 3.0.143.0.14
firebirdsqlfirebird——
firebirdsqlfirebird——
firebirdsqlfirebird>= 4.0.0 < 4.0.74.0.7
firebirdsqlfirebird>= 5.0.0 < 5.0.45.0.4

Detection & IOCsextracted from sources · hover to see the quote

  • →Look for CREATE FUNCTION statements with a crafted ENGINE name containing path separators (/ or \) or .. components, indicating path traversal attempt against the external engine plugin loader. ↗
  • →The malicious shared library's initialization code executes immediately upon loading — monitor for unexpected shared library loads or new process spawns originating from the Firebird server process (e.g., fbserver, firebird). ↗
  • →Alert on Firebird server processes loading shared libraries from non-standard or unexpected filesystem paths (outside the normal Firebird plugins directory), as the loader concatenates user-supplied ENGINE names directly into a filesystem path. ↗
  • ·Only authenticated users with CREATE FUNCTION privileges can exploit this vulnerability; restrict this privilege to trusted users as a mitigation until patching. ↗
  • ·Affected versions are Firebird prior to 5.0.4, 4.0.7, and 3.0.14; ensure detection/patching coverage spans all three supported branches. ↗
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