CVE-2026-35215 Firebird: DoS via malicious slice descriptor in slice packet

High 7.5 Published 17 Apr 2026 Updated 20 Apr 2026

An unauthenticated attacker can crash the Firebird database server by sending a crafted slice packet that triggers a division by zero error.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-35215?

CVE-2026-35215 is a high-severity denial of service vulnerability in FirebirdSQL firebird, published on 17 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Firebird is an open-source relational database management system. In versions prior to 5.0.4, 4.0.7 and 3.0.14, the sdl_desc() function does not validate the length of a decoded SDL descriptor from a slice packet. A zero-length descriptor is later used to calculate the number of slice items, causing a division by zero. An unauthenticated attacker can exploit this by sending a crafted slice packet to crash the server. This issue has been fixed in versions 5.0.4, 4.0.7 and 3.0.14.

Weakness: CWE-369

Which versions are affected by CVE-2026-35215?

It affects 1 product.

Products include Firebirdsql Firebird.

How do I fix CVE-2026-35215?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-35215 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35215 exists.

Sources

Also known as DEBIAN-CVE-2026-35215, ECHO-bd5e-9233-3d3d, GHSA-g99w-prq5-29c6, UBUNTU-CVE-2026-35215.