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…
CVE-2026-27890 · Severity: high · CVSS 8.2 · Published 2026-04-17
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.
No. Junglewise Threat Intelligence has no report of CVE-2026-27890 being exploited in the wild.
How severe is CVE-2026-27890?
High severity, with a CVSS score of 8.2, published 17 April 2026.
Which products and versions are affected?
Firebirdsql Firebird. The advisory does not name versions.
Is there a fix for CVE-2026-27890?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2026-27890?
Check whether you run Firebirdsql Firebird. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.