Vulnerability Details : CVE-2021-21708

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.
Published 2022-02-27 08:15:07
Updated 2022-10-07 14:31:22
Source PHP Group
View at NVD,   CVE.org

Products affected by CVE-2021-21708

  • PHP » PHP
    Versions from including (>=) 7.4.0 and before (<) 7.4.28
    cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
    Matching versions
  • PHP » PHP
    Versions from including (>=) 8.0.0 and before (<) 8.0.16
    cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
    Matching versions
  • PHP » PHP
    Versions from including (>=) 8.1.0 and before (<) 8.1.3
    cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
    Matching versions

Threat overview for CVE-2021-21708

Top countries where our scanners detected CVE-2021-21708
Top open port discovered on systems with this issue 80
IPs affected by CVE-2021-21708 181,228
Threat actors abusing to this issue? Yes
Find out if you* are affected by CVE-2021-21708!
*Directly or indirectly through your vendors, service providers and 3rd parties. Powered by attack surface intelligence from SecurityScorecard.

Exploit prediction scoring system (EPSS) score for CVE-2021-21708

EPSS FAQ
0.60%
Probability of exploitation activity in the next 30 days EPSS Score History
~ 79 %
Percentile, the proportion of vulnerabilities that are scored at or less

CVSS scores for CVE-2021-21708

Base Score Base Severity CVSS Vector Exploitability Score Impact Score Score Source First Seen
6.8
 MEDIUM AV:N/AC:M/Au:N/C:P/I:P/A:P
8.6
6.4
 NIST
9.8
 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.9
5.9
 NIST
8.2
 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
3.9
4.2
 PHP Group

CWE ids for CVE-2021-21708

  • The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
    Assigned by:
    • nvd@nist.gov (Primary)
    • security@php.net (Secondary)

References for CVE-2021-21708

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