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.
History

Fri, 17 Apr 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Firebirdsql
Firebirdsql firebird
Vendors & Products Firebirdsql
Firebirdsql firebird

Fri, 17 Apr 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 17 Apr 2026 19:00:00 +0000

Type Values Removed Values Added
Description 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. 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.

Fri, 17 Apr 2026 18:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Firebird has Pre-Auth DOS when Processing Out of Order CNCT_specific_data Segments
Weaknesses CWE-119
CWE-787
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-17T18:50:22.134Z

Reserved: 2026-02-24T15:19:29.716Z

Link: CVE-2026-27890

cve-icon Vulnrichment

Updated: 2026-04-17T18:50:18.684Z

cve-icon NVD

Status : Received

Published: 2026-04-17T19:16:34.993

Modified: 2026-04-17T19:16:34.993

Link: CVE-2026-27890

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-17T19:30:15Z