CVE-2026-40342 | Firebird: Path Traversal + Arbitrary File Write Leads to Remote Code Execution

Exp

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.

Published: 2026-04-17 Last update: 2026-04-27 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-40342 is rated High Exploit Risk (62.6/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.08%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-40342

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-40342

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-18 — 0.08% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-40342

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.9 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.1 6.0 [email protected]

Weakness enumeration for CVE-2026-40342

OS Trackers for CVE-2026-40342

vendor priority summary link
debian not yet assigned CVE-2026-40342 not yet assigned priority: Debian including 2 source packages (firebird3.0, firebird4.0), 8 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 4, resolved 4. https://security-tracker.debian.org/tracker/CVE-2026-40342
suse critical — https://www.suse.com/security/cve/CVE-2026-40342/
ubuntu medium CVE-2026-40342 medium priority: Ubuntu including 2 source packages (firebird3.0, firebird4.0), 12 status rows across 7 suites (bionic, focal, jammy, noble, questing, resolute, upstream): needs-triage 8, DNE 2, released 2. https://ubuntu.com/security/CVE-2026-40342

Affected software / configurations for CVE-2026-40342

Vendor Product Version Raw CPE
firebirdsql firebird < 3.0.14 cpe:2.3:a:firebirdsql:firebird:*:*:*:*:*:*:*:*
firebirdsql firebird >= 4.0.0, < 4.0.7 cpe:2.3:a:firebirdsql:firebird:*:*:*:*:*:*:*:*
firebirdsql firebird >= 5.0.0, < 5.0.4 cpe:2.3:a:firebirdsql:firebird:*:*:*:*:*:*:*:*

References for CVE-2026-40342

cvelogic Threat Intelligence