CVE-2021-43557

HighCVSS 7.5/10Last modified Jun 17, 2026

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.

Metrics

CVSS 3.1 7.5/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Weakness enumeration

CWE-77

Affected software

Vendor	Product	Versions
Apache Software Foundation	Apache APISIX	>= 1.5, < Apache APISIX 1.5*

References

http://www.openwall.com/lists/oss-security/2021/11/22/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/11/22/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/11/23/1Exploit, Mailing List, Third Party Advisory
https://lists.apache.org/thread/18jyd458ptocr31rnkjs71w4h366mv7hExploit, Mailing List, Vendor Advisory
http://www.openwall.com/lists/oss-security/2021/11/22/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/11/22/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/11/23/1Exploit, Mailing List, Third Party Advisory
https://lists.apache.org/thread/18jyd458ptocr31rnkjs71w4h366mv7hExploit, Mailing List, Vendor Advisory

Timeline

Published: Nov 22, 2021
Last modified: Jun 17, 2026
NVD status: Modified

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