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Vulnerability record · CVE-2026-27890 · published 17 April 2026

CVE-2026-27890: Firebirdsql firebird memory buffer overflow vulnerability

Firebirdsql · Firebird

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.

8.2 CVSS 3.1 High EPSS 0.72% · top 48.0% CWE-119 · Memory buffer overflowCWE-787 · Out-of-bounds write
8.2CVSS 3.1 base score
0.72%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References, 1 tagged exploit
17 Jun 2026Last modified by NVD

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/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/FirebirdSQL/firebird/releases/tag/v3.0.14 Release Notes
https://github.com/FirebirdSQL/firebird/releases/tag/v4.0.7 Release Notes
https://github.com/FirebirdSQL/firebird/releases/tag/v5.0.4 Release Notes
https://github.com/FirebirdSQL/firebird/security/advisories/GHSA-6crx-4g37-7j49 ExploitVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-27890), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.