PHP up to 7.4.27/8.0.15/8.1.2 FILTER_VALIDATE_FLOAT use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in PHP up to 7.4.27/8.0.15/8.1.2. The impacted element is an unknown function of the component FILTER_VALIDATE_FLOAT Handler. This manipulation causes use after free. This vulnerability is registered as CVE-2021-21708. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in PHP up to 7.4.27/8.0.15/8.1.2 (Programming Language Software). Affected by this vulnerability is an unknown functionality of the component FILTER_VALIDATE_FLOAT Handler. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was published 02/27/2022 as 81708. It is possible to read the advisory at bugs.php.net. This vulnerability is known as CVE-2021-21708 since 01/04/2021. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 233258 (RHEL 8 : php:7.4 (RHSA-2025:3016)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 7.4.28, 8.0.16 or 8.1.3 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (233258). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CNA Base Score: 8.2
CNA Vector (PHP Group): 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 233258
Nessus Name: RHEL 8 : php:7.4 (RHSA-2025:3016)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: PHP 7.4.28/8.0.16/8.1.3

Timelineinfo

01/04/2021 🔍
02/27/2022 +419 days 🔍
02/27/2022 +0 days 🔍
03/23/2025 +1120 days 🔍

Sourcesinfo

Product: php.org

Advisory: 81708
Status: Confirmed

CVE: CVE-2021-21708 (🔍)
GCVE (CVE): GCVE-0-2021-21708
GCVE (VulDB): GCVE-100-193915

Entryinfo

Created: 02/27/2022 13:52
Updated: 03/23/2025 05:14
Changes: 02/27/2022 13:52 (50), 03/03/2022 09:07 (1), 03/23/2025 05:14 (16)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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