# CVE-2026-27890

> Vulnerability · severity: **HIGH** (CVSS 8.2).

## 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.

## Key facts

- **CVE ID:** CVE-2026-27890
- **Published:** 2026-04-17
- **CVSS severity:** HIGH
- **CVSS base score:** 8.2
- **CWE codes:** CWE-119, CWE-787

## Affected products

- `firebirdsql:firebird`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-27890

## Citation

> AI Analytics. CVE-2026-27890. Retrieved 2026-08-03 from https://api.ai-analytics.org/cve/CVE-2026-27890. Derived from NIST NVD. Licensed CC0.

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