CVE-2026-33337Public exploitNetwork attack vector

Unauthenticated server crash via slice packet overflow

Published Apr 17, 2026 · Updated Apr 17, 2026

Buffer overflow in Firebird before 3.0.14, 4.0.7, and 5.0.4 allows remote attackers to crash the server via a crafted slice packet. The xdr_datum() function accepts a cstring longer than the slice descriptor and copies it into a buffer sized only for the slice. No authentication or user interaction is required; the published assessment establishes a server crash but does not establish code execution.

CVSS severity7.5
High
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Buffer overflow in Firebird before 3.0.14, 4.0.7, and 5.0.4 allows remote attackers to crash the server via a crafted slice packet. The xdr_datum() function accepts a cstring longer than the slice descriptor and copies it into a buffer sized only for the slice. No authentication or user interaction is required; the published assessment establishes a server crash but does not establish code execution.

The record

CVE
CVE-2026-33337
Published
Apr 17, 2026
Updated
Apr 17, 2026
Vendor
FirebirdSQL
Product
Firebird
Classifications
CWE-502, CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.0.0, < 3.0.14
  2. Affected versionversion=>= 4.0.0, < 4.0.7
  3. Affected versionversion=>= 5.0.0, < 5.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FirebirdSQL · Firebirdversion=>= 3.0.0, < 3.0.14; version=>= 4.0.0, < 4.0.7; version=>= 5.0.0, < 5.0.4

Published CVSS scores

7.5UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo