SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

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,…

CRITICAL 9.8EPSS 3.00%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (3.00%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
3.00% probability · 87th percentile
CISA KEV
Not listed
Weakness
CWE-416
Affected
php/php
Source
security@php.net

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.