CVE-2021-39156

HIGH8.1EPSS 0.24%

Istio Fragments in Path May Lead to Authorization Policy Bypass

Published: 8/30/2021Modified: 3/13/2026

Description

### Impact Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. ### Patches * Istio 1.11.1 and above * Istio 1.10.4 and above * Istio 1.9.8 and above ### Workarounds A Lua filter may be written to normalize the path. This is similar to the Path normalization presented in the [Security Best Practices](https://istio.io/latest/docs/ops/best-practices/security/#case-normalization) guide. ### References More details can be found in the [Istio Security Bulletin](https://istio.io/latest/news/security/istio-security-2021-008) ### For more information If you have any questions or comments about this advisory, please email us at [email protected]

Affected packages (1)

CVSS scores

SourceVersionSeverityVector
osvCVSS 3.1HIGH8.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

References (4)