Auth bypass in Istio

CVE-2021-31921

Istio before 1.8.6 and 1.9.x before 1.9.5 contains a remotely exploitable vulnerability where an external client can access unexpected services in the cluster, bypassing authorization checks, when a gateway is configured with AUTO_PASSTHROUGH routing configuration.

Vulnerability class: Broken Access Control

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.015 (72.4th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 72.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-31921: held from 0.015 to 0.015.

EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-31921?
CVE-2021-31921 is a critical-severity vulnerability in Istio, classified under Missing Authorization. CVSS score: 9.8/10. Published 2021-06-02.
How severe is CVE-2021-31921?
Critical severity. CVSS v3 base score is 9.8 out of 10.