CVE-2021-21708 - CVE House

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Status published High CVE-2021-21708

UAF due to php_filter_float() failing

8.2 CVSS

Vulnerability Description

In PHP versions 7.4.x below 7.4.28, 8.0.x below 8.0.16, and 8.1.x below 8.1.3, when using filter functions with FILTER_VALIDATE_FLOAT filter and min/max limits, if the filter fails, there is a possibility to trigger use of allocated memory after free, which can result it crashes, and potentially in overwrite of other memory chunks and RCE. This issue affects: code that uses FILTER_VALIDATE_FLOAT with min/max limits.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

dukk at softdev dot online

References

More from PHP Group

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Affected Vendor

PHP Group

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Affected Software

PHP

Vulnerable Versions:

7.4.x, 8.0.X, 8.1.X

Timeline

Official Publish: February 27th, 2022

Last Modified: September 17th, 2024

Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

Weaknesses (CWE)

MITRE ATT&CK TTPs

T1190 Exploit Public-Facing Application

T1068 Exploitation for Privilege Escalation

Privilege Escalation

T1055 Process Injection

Defense Evasion

T1105 Ingress Tool Transfer

Command and Control

T1485 Data Destruction