TI-2026-22234 Aliases CVE-2026-27890

Firebird has Pre-Auth DOS when Processing Out of Order CNCT_specific_data Segments

HIGH 75CWE-119Published 2026-04-17 · Updated 2026-04-17

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · Low · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00465 40th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed firebird (FirebirdSQL): 3.0.14, 4.0.7, 5.0.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
FirebirdSQL	firebird	3.0.0 to before 3.0.14; 4.0.0 to before 4.0.7; 5.0.0 to before 5.0.4	3.0.14, 4.0.7, 5.0.4	Patch available	CNA

firebird VendorFirebirdSQL Affected 3.0.0 to before 3.0.14; 4.0.0 to before 4.0.7; 5.0.0 to before 5.0.4 Fixed in 3.0.14, 4.0.7, 5.0.4 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:firebirdsql:firebird::::::::	before 3.0.14; 4.0.0 to before 4.0.7; 5.0.0 to before 5.0.4	Vulnerable	FirebirdSQL

cpe:2.3:a:firebirdsql:firebird:*:*:*:*:*:*:*:* Versions before 3.0.14; 4.0.0 to before 4.0.7; 5.0.0 to before 5.0.4 Vulnerable ·FirebirdSQL

Remediation

Fix · CNA firebird (FirebirdSQL) Fixed in 3.0.14, 4.0.7, 5.0.4

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product

Red Hat

Timeline

2026-10-02 Threatist record created from CVE-2026-27890
2026-10-25 EPSS moved to the below the 50th percentile

References

Exploit 1

https://github.com/FirebirdSQL/firebird/security/advisories/GHSA-6crx-4g37-7j49

Other 3

TI-2026-22559 Firebird Null Pointer Dereference via CryptCallback causes DOS CVSS 3.1HIGH 8.2
TI-2026-27368 Firebird: DoS via malicious slice descriptor in slice packet CVSS 3.1HIGH 7.5
TI-2026-26527 Firebird: DoS via `op_response` packet from client CVSS 3.1HIGH 7.5
TI-2026-25747 Firebird has a buffer overflow when parsing corrupted slice packets CVSS 3.1HIGH 7.5
TI-2026-22547 Firebird has potential server crash via null pointer dereference when processing op_slice packet CVSS 3.1HIGH 7.5
TI-2008-00362 Integer overflow in Firebird SQL 1.0.3 and earlier, 1.5.x before 1.5.6, 2.0.x before… CVSS 2.0HIGH 7.8

See all 45 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences