CVE-2026-27890
If segments arrive out of order, the Array class's grow() method computes a negative size value, causing a SIGSEGV crash.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.2 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- EPSS
- 0.46% probability · 39th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-119, CWE-787
- Affected
- firebirdsql/firebird
- Source
- security-advisories@github.com
References
- https://github.com/FirebirdSQL/firebird/releases/tag/v3.0.14Release Notes
- https://github.com/FirebirdSQL/firebird/releases/tag/v4.0.7Release Notes
- https://github.com/FirebirdSQL/firebird/releases/tag/v5.0.4Release Notes
- https://github.com/FirebirdSQL/firebird/security/advisories/GHSA-6crx-4g37-7j49Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.