CVE-2026-27890

Summary

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.

Affected Software

VendorProductVersion RangeStatus
FirebirdSQLfirebird>= 3.0.0, < 3.0.14affected
FirebirdSQLfirebird>= 4.0.0, < 4.0.7affected
FirebirdSQLfirebird>= 5.0.0, < 5.0.4affected

Weaknesses

  • CWE-119: CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-787: CWE-787: Out-of-bounds Write

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

References