{"cve":"CVE-2021-43557","nvd":{"published":"2021-11-22T09:15:07.627","modified":"2026-06-17T04:11:07.910","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-77"],"references":["http://www.openwall.com/lists/oss-security/2021/11/22/1","http://www.openwall.com/lists/oss-security/2021/11/22/2","http://www.openwall.com/lists/oss-security/2021/11/23/1","https://lists.apache.org/thread/18jyd458ptocr31rnkjs71w4h366mv7h","http://www.openwall.com/lists/oss-security/2021/11/22/1"],"products":["apache:apisix"],"source":"nvd","synced_at":"2026-10-19T21:25:41.256909649+00:00"},"epss":{"cve":"CVE-2021-43557","score":0.13044,"percentile":0.96343,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}