Home/CVE/Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when pro
CVE

CVE-2026-27890

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when pro

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when processing CNCT_specific_data segments during authentication, the server assumes segments arrive in strictly ascending order. If segments arrive out of order, the Array class's grow() method computes a negative size value, causing a SIGSEGV crash.

An unauthenticated attacker who knows only the server's IP and port can exploit this to crash the server. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

HIGH · CVSS 8.2 EPSS 0.00584
Act now
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-787Out-of-bounds Write
▤

Affected Products & Versions

3
firebirdsql firebird< 3.0.14
firebirdsql firebird>= 4.0.0 and < 4.0.7
firebirdsql firebird>= 5.0.0 and < 5.0.4
⚠

Public Exploits & PoCs

1
pocgithub.com · GHSA-6crx-4g37-7j49github.com
▣

Scoring & Timeline

8.2
HIGH · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD17 Apr 2026 · 07:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

1
suse-csafSUSE-SU-2026:1868-1
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/FirebirdSQL/firebird/releases/tag/v3.0.14Release Notes
https://github.com/FirebirdSQL/firebird/releases/tag/v4.0.7Release Notes
https://github.com/FirebirdSQL/firebird/releases/tag/v5.0.4Release Notes
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