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Fencer Intel
high 7.5

CVE-2026-33337 json

Firebird has a buffer overflow when parsing corrupted slice packets

published 6mo ago modified 14d ago also EUVD-2026-23482

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

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 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.

Patch / fix

  • firebirdsql firebird 3.0.14, 4.0.7, 5.0.4
  • firebird3.0 Debian 14 3.0.14.ds7-1
  • firebird4.0 Debian 14 4.0.7.3271.ds6-1

debian advisories DEBIAN-CVE-2026-33337

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33337 updated cvss 7.5

Firebird: Firebird: Denial of Service via buffer overflow in slice packet deserialization

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/FirebirdSQL/firebird/security/advisories/GHSA-89mq-229g-x47p referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • FirebirdSQL firebird

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.