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CVE-2026-33337: Firebird is an open-source relational database management system

48
This week
HIGH 7.5REMOTEUPGRADE

CVE-2026-33337 is a high-severity flaw (CVSS 7.5) affecting firebird. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 secu

Why this priority

  • High severity
  • Public exploit reference
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score7.5 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.5% (top 55%)
CISA exploited listNo
WeaknessCWE-120, CWE-502
Published2026-04-17
Last modified2026-10-26
Publisher (CNA): GitHub, Inc. · Vendor: firebirdsql

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Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

firebirdsql firebird UPGRADE
Affected: >= 3.0.0 and < 3.0.14 · >= 4.0.0 and < 4.0.7 · >= 5.0.0 and < 5.0.4
Fixed in: 3.0.14, 4.0.7, 5.0.4
Safe to downgrade to: a release before 3.0.0
1. Check installed version
apt-cache policy firebird || rpm -q firebird || firebird --version
2. UPGRADE to 3.0.14 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade firebird
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade firebird
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)
apt-cache madison firebird sudo apt install firebird=<VERSION_BEFORE_3.0.0> sudo apt-mark hold firebird
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list firebird sudo dnf downgrade firebird-<VERSION_BEFORE_3.0.0> sudo dnf versionlock add firebird
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-33337?

firebird: upgrade to 3.0.14, 4.0.7, 5.0.4. Exact commands for each OS are on this page.

Is CVE-2026-33337 being exploited?

CVE-2026-33337 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-33337 affect?

CVE-2026-33337 affects firebird. Severity is high (CVSS 7.5). 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 descri

How urgent is CVE-2026-33337?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

References

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