CVE-2026-28214 FirebirdSQL CVE debrief

Who should care

Defenders responsible for Firebird database management systems should assess exposure and apply patches if necessary. This includes verifying Firebird version and exposure, and prioritizing patching for affected versions. Defenders should also restrict INSERT privileges on tables and monitor for suspicious activity. The vulnerability can be exploited by an authenticated user with INSERT privileges on any table, causing a denial-of-service against the 6

Why it matters

CVE-2026-28214 is a denial-of-service vulnerability in Firebird that can be exploited by an authenticated user with INSERT privileges. Defenders should prioritize verifying exposure and applying patches for affected versions.

• Denial of service against the server
• Potential disruption of database services
• Need for verification of Firebird version and exposure
• Priority for applying patches or mitigations

Technical summary

The ClumpletReader::getClumpletSize() function in Firebird can overflow the totalLength value when parsing a Wide type clumplet, causing an infinite loop. An authenticated user with INSERT privileges on any table can exploit this via a crafted Batch Parameter Block. This issue has been fixed in versions 5.0.4, 4.0.7, and 3.0.14. The vulnerability affects Firebird versions prior to 5.0.4, 4.0.7, and 3.0.14. Defenders should prioritize verifying exposure and applying patches for affected versions. The CVE record and NVD entry provide details on the vulnerability, affected versions, and fixed versions.

Defensive priority

Defenders should prioritize verifying exposure and applying patches for Firebird versions prior to 5.0.4, 4.0.7, and 3.0.14.

Recommended defensive actions

• Verify Firebird version and apply patches if necessary
• Restrict INSERT privileges on tables
• Monitor for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, affected versions, and fixed versions. The ClumpletReader::getClumpletSize() function can overflow the totalLength value when parsing a Wide type clumplet, causing an infinite loop. An authenticated user with INSERT privileges on any table can exploit this via a crafted Batch Parameter Block. The issue has been fixed in versions 5.0.4, 4.0.7, and 3.0.14. Evidence limits suggest verifying exposure and applying patches for affected versions. Defenders should prioritize 5

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.