RCE in Firebirdsql Firebird
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 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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (57.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 57.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.008 · change: +0.002
Affected products
- Firebirdsql Firebird — versions < 3.0.14, >= 4.0.0, < 4.0.7, >= 5.0.0, < 5.0.4
Weakness classification (CWE)
References
- github.com/FirebirdSQL/firebird/security/advisories/GHSA-7pxc-h3rv-r257 (Exploit, Vendor Advisory)
- github.com/FirebirdSQL/firebird/releases/tag/v3.0.14 (Release Notes)
- github.com/FirebirdSQL/firebird/releases/tag/v4.0.7 (Release Notes)
- github.com/FirebirdSQL/firebird/releases/tag/v5.0.4 (Release Notes)
Frequently asked questions
- What is CVE-2026-40342?
- CVE-2026-40342 is a critical-severity vulnerability in Firebirdsql Firebird, classified under Path Traversal. CVSS score: 9.9/10. Published 2026-04-17.
- How severe is CVE-2026-40342?
- Critical severity. CVSS v3 base score is 9.9 out of 10.