CVE-2026-27890
High
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.
SeverityHigh
CVSS8.2
Exploit probability—
ProductFirebird
PublishedApr 17, 2026
First seenApr 17, 2026
How to fix
Update
- firebirdsql firebird3.0.14, 4.0.7, 5.0.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| firebirdsql firebird | v < 3.0.14, 4.0.0 ≤ v < 4.0.7, 5.0.0 ≤ v < 5.0.4 | 3.0.14, 4.0.7, 5.0.4 |
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