CVE Intelligence
Critical File handling exploit reference

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

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 Apr 17, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.8% (30-day exploitation probability)+9
  • Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.85%
ahead of 57% of scored CVEs · Oct 14, 2026
Affects
Firebirdsql
Firebird
CVSS base
9.9
Critical · 2 source(s)
Prioritization reference: 10.0 provisional

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Firebirdsql Firebird).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Firebirdsql Firebird < 3.0.14≥ 4.0.0 and < 4.0.7≥ 5.0.0 and < 5.0.4 Vulnerable NIST National Vulnerability Database
Firebirdsql Firebird version < 3.0.14version >= 4.0.0, < 4.0.7version >= 5.0.0, < 5.0.4 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
10.0 CVSS 3.1 Critical — — GitHub_M via CVE Program (cve.org) e CISA ADP
9.9 CVSS 3.1 Critical 3.1 6.0 security-advisories@github.com via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-22 · Path Traversal

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.85%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Monitor file creation in web directories and paths with traversal sequences (../).
web/proxy/WAF logsnetwork IDS/IPSfile integrity (FIM)endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · firebirdsql/firebird
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 9.9
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Apr 17, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

Elsewhere on this site

Firebirdsql
every CVE for this vendor
File handling
same class
CWE-22
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-35215 Firebird: DoS via malicious slice descriptor in slice packet Apr 17, 2026
  • CVE-2026-34232 Firebird: DoS via `op_response` packet from client Apr 17, 2026
  • CVE-2026-33337 Firebird has a buffer overflow when parsing corrupted slice packets Apr 17, 2026
  • CVE-2026-28212 Firebird has potential server crash via null pointer dereference when processing op_slice packet Apr 17, 2026
  • CVE-2026-28214 Firebird server hangs when using specific clumplet on batch creation Apr 17, 2026
  • CVE-2026-28224 Firebird Null Pointer Dereference via CryptCallback causes DOS Apr 17, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-40342 is "Firebird: Path Traversal + Arbitrary File Write Leads to Remote Code Execution", rated Critical. It affects Firebird (Firebirdsql); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.9 describes technical severity. EPSS 0.85% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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