Vulnerability Details 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 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.001
EPSS Ranking 29.1%
CVSS Severity
CVSS v3 Score 8.2
References
Products affected by CVE-2026-27890
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cpe:2.3:a:firebirdsql:firebird:-
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cpe:2.3:a:firebirdsql:firebird:1.0
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cpe:2.3:a:firebirdsql:firebird:1.0.2
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cpe:2.3:a:firebirdsql:firebird:1.0.3
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cpe:2.3:a:firebirdsql:firebird:1.5
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cpe:2.3:a:firebirdsql:firebird:1.5.0.4306
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cpe:2.3:a:firebirdsql:firebird:1.5.1
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cpe:2.3:a:firebirdsql:firebird:1.5.2
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cpe:2.3:a:firebirdsql:firebird:1.5.2.4731
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cpe:2.3:a:firebirdsql:firebird:1.5.3.4870
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cpe:2.3:a:firebirdsql:firebird:1.5.4.4910
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cpe:2.3:a:firebirdsql:firebird:1.5.5
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cpe:2.3:a:firebirdsql:firebird:1.5.6
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cpe:2.3:a:firebirdsql:firebird:2.0.0
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cpe:2.3:a:firebirdsql:firebird:2.0.0.12748
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cpe:2.3:a:firebirdsql:firebird:2.0.1
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cpe:2.3:a:firebirdsql:firebird:2.0.1.12855
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cpe:2.3:a:firebirdsql:firebird:2.0.2
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cpe:2.3:a:firebirdsql:firebird:2.0.3
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cpe:2.3:a:firebirdsql:firebird:2.0.4
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cpe:2.3:a:firebirdsql:firebird:2.0.5
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cpe:2.3:a:firebirdsql:firebird:2.0.6
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cpe:2.3:a:firebirdsql:firebird:2.0.7
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cpe:2.3:a:firebirdsql:firebird:2.1
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cpe:2.3:a:firebirdsql:firebird:2.1.0
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cpe:2.3:a:firebirdsql:firebird:2.1.1
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cpe:2.3:a:firebirdsql:firebird:2.1.2
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cpe:2.3:a:firebirdsql:firebird:2.1.3
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cpe:2.3:a:firebirdsql:firebird:2.1.4
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cpe:2.3:a:firebirdsql:firebird:2.1.5
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cpe:2.3:a:firebirdsql:firebird:2.1.6
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cpe:2.3:a:firebirdsql:firebird:2.1.7
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cpe:2.3:a:firebirdsql:firebird:2.1_beta
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cpe:2.3:a:firebirdsql:firebird:2.5
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cpe:2.3:a:firebirdsql:firebird:2.5.0
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cpe:2.3:a:firebirdsql:firebird:2.5.1
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cpe:2.3:a:firebirdsql:firebird:2.5.2
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cpe:2.3:a:firebirdsql:firebird:2.5.3
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cpe:2.3:a:firebirdsql:firebird:2.5.4
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cpe:2.3:a:firebirdsql:firebird:2.5.5
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cpe:2.3:a:firebirdsql:firebird:2.5.6
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cpe:2.3:a:firebirdsql:firebird:2.5.7
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cpe:2.3:a:firebirdsql:firebird:2.5.8
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cpe:2.3:a:firebirdsql:firebird:2.5.9
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cpe:2.3:a:firebirdsql:firebird:3.0
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cpe:2.3:a:firebirdsql:firebird:3.0.0
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cpe:2.3:a:firebirdsql:firebird:3.0.1
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cpe:2.3:a:firebirdsql:firebird:3.0.10
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cpe:2.3:a:firebirdsql:firebird:3.0.11
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cpe:2.3:a:firebirdsql:firebird:3.0.12
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cpe:2.3:a:firebirdsql:firebird:3.0.13
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cpe:2.3:a:firebirdsql:firebird:3.0.2
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cpe:2.3:a:firebirdsql:firebird:3.0.3
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cpe:2.3:a:firebirdsql:firebird:3.0.4
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cpe:2.3:a:firebirdsql:firebird:3.0.5
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cpe:2.3:a:firebirdsql:firebird:3.0.6
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cpe:2.3:a:firebirdsql:firebird:3.0.7
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cpe:2.3:a:firebirdsql:firebird:3.0.8
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cpe:2.3:a:firebirdsql:firebird:3.0.9
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cpe:2.3:a:firebirdsql:firebird:4.0.0
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cpe:2.3:a:firebirdsql:firebird:4.0.1
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cpe:2.3:a:firebirdsql:firebird:4.0.2
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cpe:2.3:a:firebirdsql:firebird:4.0.3
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cpe:2.3:a:firebirdsql:firebird:4.0.4
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cpe:2.3:a:firebirdsql:firebird:4.0.5
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cpe:2.3:a:firebirdsql:firebird:4.0.6
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cpe:2.3:a:firebirdsql:firebird:5.0.0
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cpe:2.3:a:firebirdsql:firebird:5.0.1
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cpe:2.3:a:firebirdsql:firebird:5.0.2
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cpe:2.3:a:firebirdsql:firebird:5.0.3