CVE-2026-27890

Name of the Vulnerable Software and Affected Versions Firebird versions prior to 5.0.4 Firebird versions prior to 4.0.7 Firebird versions prior to 3.0.14

Description An issue exists during authentication when processing CNCT specific data segments. The server assumes these segments arrive in strictly ascending order; however, if they arrive out of order, the grow() method of the Array class computes a negative size value, leading to a SIGSEGV crash (a segmentation fault where the program attempts to access a memory location that it is not allowed to access). An unauthenticated attacker with knowledge of the server IP and port can trigger this crash.

Recommendations Update to version 5.0.4 Update to version 4.0.7 Update to version 3.0.14