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Fencer Intel
critical 10.0

CVE-2026-40342 json

Firebird: Path Traversal + Arbitrary File Write Leads to Remote Code Execution

published 6mo ago modified 14d ago also EUVD-2026-23496

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

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.

Patch / fix

  • firebirdsql firebird 3.0.14, 4.0.7, 5.0.4
  • firebird3.0 Debian 14 3.0.14.ds7-1
  • firebird4.0 Debian 14 4.0.7.3271.ds6-1

debian advisories DEBIAN-CVE-2026-40342

Is CVE-2026-40342 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-40342 updated cvss 7.8

Firebird: Firebird: Arbitrary code execution via path traversal in external engine plugin loader

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
6mo ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/FirebirdSQL/firebird/security/advisories/GHSA-7pxc-h3rv-r257 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • FirebirdSQL firebird

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-427 Uncontrolled Search Path Element
  • CWE-73 External Control of File Name or Path
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.