HIGH

CVE-2021-43557

CVSS v3

7.5

HIGH

EPSS Score

58.3%

exploit probability

CISA KEV

No

known exploited

Exploitation

SSVC status

Description

The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like `//internal/` can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.

Technical details

Published
11/22/2021

Frequently asked questions

What is CVE-2021-43557?

The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like `//internal/` can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.

Is CVE-2021-43557 actively exploited?

Active exploitation of CVE-2021-43557 has not been confirmed. The EPSS score is 58.3%, indicating the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-43557?

CVE-2021-43557 has a CVSS v3 base score of 7.5 (HIGH severity).

Is CVE-2021-43557 affecting your environment?

Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.