CVE-2021-21705

Public Exploit
Incorrect URL validation in FILTER_VALIDATE_URL

Description

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 URL validation functionality via filter_var() function with FILTER_VALIDATE_URL parameter, an URL with invalid password field can be accepted as valid. This can lead to the code incorrectly parsing the URL and potentially leading to other security implications - like contacting a wrong server or making a wrong access decision.

Category

4.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.31%
Vendor Advisory gentoo.org Vendor Advisory php.net Vendor Advisory oracle.com
Affected: PHP Group PHP
Published at:
Updated at:

References

Link Tags
https://bugs.php.net/bug.php?id=81122 issue tracking patch vendor advisory exploit
https://www.oracle.com/security-alerts/cpujan2022.html patch vendor advisory
https://security.netapp.com/advisory/ntap-20211029-0006/ third party advisory
https://security.gentoo.org/glsa/202209-20 third party advisory vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-21705?
CVE-2021-21705 has been scored as a medium severity vulnerability.
How to fix CVE-2021-21705?
To fix CVE-2021-21705, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-21705 being actively exploited in the wild?
It is possible that CVE-2021-21705 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-21705?
CVE-2021-21705 affects PHP Group PHP.
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