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Vulnerability · Published Aug 24, 2021 · Assigned by GitHub_M

CVE-2021-39156Fragments in Path May Lead to Authorization Policy Bypass

High 8.1

In plain English

A high-severity incorrect authorization in istio from istio. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 68% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.1High
Exploit odds (30 days)1.2%top 32.3% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack tooling1Public PoC

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Goistio.io/istio1.9.8GHSA-hqxw-mm44-gc4r
Goistio.io/istio1.10.4GHSA-hqxw-mm44-gc4r
Goistio.io/istio1.11.1GHSA-hqxw-mm44-gc4r

Affected products (as reported)

VendorProductVersions
istio istio < 1.9.8>= 1.10.0, < 1.10.4>= 1.11.0, < 1.11.1

Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

References