Cyber Resilience

CVE-2021-43557

HighPublic PoCRCE

Published: 22 November 2021

Published
22 November 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.5526 98.1th percentile
Risk Priority 48 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-43557 is a high-severity Command Injection (CWE-77) vulnerability in Apache Apisix. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 1.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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,…

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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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

apache
apisix
≤ 2.10.2

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References