CVE-2021-39156
HIGHIstio < 1.9.8 - Authorization Bypass via URI Fragment
Title source: llmExploitation Summary
EIP tracks 1 public exploit for CVE-2021-39156. PoCs published by anonymousAIware2026.
AI-analyzed exploit summary This repository demonstrates CVE-2021-39156, an SSRF vulnerability in XStream where an attacker can bypass Istio AuthorizationPolicy by exploiting a misconfigured API gateway route. The PoC includes a microservice architecture with an API gateway that forwards requests to internal services, bypassing the deny rule for the /admin endpoint.
Description
Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. 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 are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.
Exploits (1)
This repository demonstrates CVE-2021-39156, an SSRF vulnerability in XStream where an attacker can bypass Istio AuthorizationPolicy by exploiting a misconfigured API gateway route. The PoC includes a microservice architecture with an API gateway that forwards requests to internal services, bypassing the deny rule for the /admin endpoint.
References (2)
Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N