CVE-2026-28214Public exploitNetwork attack vector

Authenticated server hang via clumplet length overflow

Published Apr 17, 2026 · Updated Apr 17, 2026

Denial of service in Firebird before 3.0.14, 4.0.7, and 5.0.4 allows remote authenticated users to hang the server via a batch request. ClumpletReader::getClumpletSize() adds untrusted Wide clumplet length fields in a size type that wraps, so parsing never advances past the malformed Batch Parameter Block. Reachability requires database authentication and INSERT privilege on a table; triggering the flaw indefinitely occupies server request processing.

CVSS severity6.0
Medium
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Denial of service in Firebird before 3.0.14, 4.0.7, and 5.0.4 allows remote authenticated users to hang the server via a batch request. ClumpletReader::getClumpletSize() adds untrusted Wide clumplet length fields in a size type that wraps, so parsing never advances past the malformed Batch Parameter Block. Reachability requires database authentication and INSERT privilege on a table; triggering the flaw indefinitely occupies server request processing.

The record

CVE
CVE-2026-28214
Published
Apr 17, 2026
Updated
Apr 17, 2026
Vendor
Firebird Project
Product
Firebird
Classifications
CWE-190, CWE-835, T1499.004
Attack vector
network
Privileges
authenticated

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 privilegesauthenticated

What is affected?

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

Published CVSS scores

6.0GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Application or System Exploitation

Public exploit references

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

Technologies

Your stack

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Your stack

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