CVE-2021-32779

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Summary

CVECVE-2021-32779
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-08-24 21:15:00 UTC
Updated2022-10-25 15:56:00 UTC
DescriptionEnvoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions envoy incorrectly handled a URI '#fragment' element as part of the path element. Envoy is configured with an RBAC filter for authorization or similar mechanism with an explicit case of a final "/admin" path element, or is using a negative assertion with final path element of "/admin". The client sends request to "/app1/admin#foo". In Envoy prior to 1.18.0, or 1.18.0+ configured with path_normalization=false. Envoy treats fragment as a suffix of the query string when present, or as a suffix of the path when query string is absent, so it evaluates the final path element as "/admin#foo" and mismatches with the configured "/admin" path element. In Envoy 1.18.0+ configured with path_normalization=true. Envoy transforms this to /app1/admin%23foo and mismatches with the configured /admin prefix. The resulting URI is sent to the next server-agent with the offending "#foo" fragment which violates RFC3986 or with the nonsensical "%23foo" text appended. A specifically constructed request with URI containing '#fragment' element delivered by an untrusted client in the presence of path based request authorization resulting in escalation of Privileges when path based request authorization extensions. Envoy versions 1.19.1, 1.18.4, 1.17.4, 1.16.5 contain fixes that removes fragment from URI path in incoming requests.

Risk And Classification

Problem Types: CWE-697

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Envoyproxy Envoy All All All All
Application Envoyproxy Envoy 1.19.0 All All All

References

ReferenceSourceLinkTags
Incorrectly handling of URI '#fragment' element as part of the path element · Advisory · envoyproxy/envoy · GitHub CONFIRM github.com
Version history — envoy tag-v1.19.0 documentation MISC www.envoyproxy.io
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 159555 Oracle Enterprise Linux Security Update for olcne (ELSA-2021-9525)
  • 159556 Oracle Enterprise Linux Security Update for olcne (ELSA-2021-9526)
  • 159558 Oracle Enterprise Linux Security Update for olcne istio istio kubernetes (ELSA-2021-9546)
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