Buffer overflow in Firebirdsql Firebird
CVE-2026-33337
Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, when deserializing a slice packet, the xdr_datum() function does not validate that a cstring length conforms to the slice descriptor bounds, allowing a cstring longer than the allocated buffer to overflow it. An unauthenticated attacker can exploit this by sending a crafted packet to the server, potentially causing a crash or other security impact. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.
Vulnerability class: Buffer Overflow
EPSS: 0.005 (43.6th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Firebirdsql Firebird — versions >= 3.0.0, < 3.0.14, >= 4.0.0, < 4.0.7, >= 5.0.0, < 5.0.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-33337?
- CVE-2026-33337 is a high-severity vulnerability in Firebirdsql Firebird, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.5/10. Published 2026-04-17.
- How severe is CVE-2026-33337?
- High severity. CVSS v3 base score is 7.5 out of 10.