CVE-2021-21704: Multiple vulnerabilities in Firebird client extension

Published Jun 21, 2021
·
Updated

Fixed bug (Crash while parsing blob data in firebirdfetchblob). (CVE-2021-21704)

Other sources

In PHP versions 7.3.x below 7.3.29, 7.4.x below 7.4.21 and 8.0.x below 8.0.8, when using Firebird PDO driver extension, a malicious database server could cause crashes in various database functions, such as getAttribute(), execute(), fetch() and others by returning invalid response data that is not parsed correctly by the driver. This can result in crashes, denial of service or potentially memory corruption.

MITRE

Multiple vulnerabilities in Firebird client extension

Microsoft

Affected Software

6 affected componentsFixes available
PHP PHP>=7.3.0<7.3.29
PHP PHP>=7.4.0<7.4.21
PHP PHP>=8.0.0<8.0.8
NetApp Clustered Data ONTAP
PHP PHP<8.0.8
8.0.8
Microsoft cbl2 php

Event History

Jul 1, 2021
CVE Published
via PHP·12:00 AM
Oct 4, 2021
CVE Published
via MITRE·04:00 AM
Data Sourced
via MITRE·04:00 AM
DescriptionSeverityWeakness
Oct 1, 2025
Data Sourced
via Microsoft·11:11 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·11:11 PM
Affected Software
Updated
via Microsoft·11:11 PM
DescriptionSeverity
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2021-21704?

The severity of CVE-2021-21704 is medium with a CVSS score of 5.9.

2

What is the affected software for CVE-2021-21704?

The affected software for CVE-2021-21704 is PHP versions 7.3.x below 7.3.29, 7.4.x below 7.4.21, and 8.0.x below 8.0.8, as well as NetApp Clustered Data ONTAP.

3

How can a malicious database server exploit CVE-2021-21704?

A malicious database server can exploit CVE-2021-21704 by returning invalid response data that can cause crashes in various database functions.

4

Are there any known fixes for CVE-2021-21704?

Yes, the fix for CVE-2021-21704 is available in PHP version 8.0.8.

5

Where can I find more information about CVE-2021-21704?

You can find more information about CVE-2021-21704 on the PHP website and the bug report links provided.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203