CVE-2023-27488
criticalpriority · track · 39EPSS 0.007 · 54 %ileDEEUUSEPSS · scored 2026-10-27
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, escalation of privileges is possible when `failure_mode_allow: true` is configured for `ext_authz` filter. For affected components that are used for logging and/or visibility, requests may not be logged by the receiving service. When Envoy was configured to use ext_authz, ext_proc, tap, ratelimit filters, and grpc access log service and an http header with non-UTF-8 data was received, Envoy would generate an invalid protobuf message and send it to the configured service. The receiving service would typically generate an error when decoding the protobuf message. For ext_authz that was configured with ``failure_mode_allow: true``, the request would have been allowed in this case. For the other services, this could have resulted in other unforeseen errors such as a lack of visibility into requests. As of versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, Envoy by default sanitizes the values sent in gRPC service calls to be valid UTF-8, replacing data that is not valid UTF-8 with a `!` character. This behavioral change can be temporarily reverted by setting runtime guard `envoy.reloadable_features.service_sanitize_non_utf8_strings` to false. As a workaround, one may set `failure_mode_allow: false` for `ext_authz`.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- Fixedopenshift-service-mesh/proxyv2-rhel8@sha256:29246b072bb2829c8e86b41e7ecdf8e3845d64b9f87247cf81a6088a3d040d3c_ppc64le as a component of RHOSSM 2.2 for RHEL 8redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2023:4623 - Fixedopenshift-service-mesh/proxyv2-rhel8@sha256:60036f920ef18e80ed97dadb25e4d6ae2e63f74e04c51e18badf22aae25a7f50_s390x as a component of RHOSSM 2.2 for RHEL 8redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2023:4623 - Fixedopenshift-service-mesh/proxyv2-rhel8@sha256:d8a8d11de42f5105b47b89bf715945825fa496d05aa1fcbcbd230bad2d31d59f_amd64 as a component of RHOSSM 2.2 for RHEL 8redhat_csaf
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2023:4623
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 5.4–9.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (37)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- RHSA-2023:4623Red Hat Security Advisory: Red Hat OpenShift Service Mesh 2.2.9 security update2023-08-11csaf · redhat_csafUS
Red Hat OpenShift Service Mesh 2.2.9 Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
- WID-SEC-W-2023-2058Red Hat OpenShift Service Mesh und Service Mesh Containers: Mehrere SchwachstellenDeutsch2023-08-13csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Red Hat OpenShift Service Mesh und Service Mesh Containers, sowie Red Hat Enterprise Linux ausnutzen, um einen Denial of Service Zustand herbeizuführen, Dateien zu manipulieren, Sicherheitsvorkehrungen zu umgehen oder Informationen offenzulegen.
- BIT-envoy-2023-27488Envoy gRPC client produces invalid protobuf when an HTTP header with non-UTF8 value is received.2024-03-06vendor · osvUS
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, escalation of privileges is possible when `failure_mode_allow: true` is configured for `ext_authz` filter. For affected components that are used for logging and/or visibility, requests may not be logged by the receiving service. When Envoy was configured to use ext_authz, ext_proc, tap, ratelimit filters, and grpc access log service and an http header with non-UTF-8 data was received, Envoy would generate an invalid protobuf message and send it to the configured service. The receiving service would typically generate an error when decoding the protobuf message. For ext_authz that was configured with ``failure_mode_allow: true``, the request would have been allowed in this case. For the other services, this could have resulted in other unforeseen errors such as a lack of visibility into requests. As of versions 1.26.0, 1.25.3, 1.24.4, 1.23.6, and 1.22.9, Envoy by default sanitizes the values sent in gRPC service calls to be valid UTF-8, replacing data that is not valid UTF-8 with a `!` character. This behavioral change can be temporarily reverted by setting runtime guard `envoy.reloadable_features.service_sanitize_non_utf8_strings` to false. As a workaround, one may set `failure_mode_allow: false` for `ext_authz`.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (6)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2023-27488cnnvd
- https://cxsecurity.com/cveshow/CVE-2023-27488/cnnvd
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-9g5w-hqr3-w2phcnnvd
- https://www.auscert.org.au/bulletins/ESB-2023.4653cnnvd
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-9g5w-hqr3-w2phenisa_euvd
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-9g5w-hqr3-w2phExploitMitigationVendor Advisorynvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan