CVE-2021-31921 is a critical vulnerability affecting Istio versions prior to 1.8.6 and 1.9.5, allowing external clients to bypass authorization and access unexpected services within a cluster when a gateway uses AUTO_PASSTHROUGH routing. With a CVSS score of 9.8, it represents a severe risk due to its network-based attack vector, low attack complexity, and complete compromise potential (confidentiality, integrity, availability). While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community discussion, indicating awareness and potential interest.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 1.8.6CPE matchmatch criteria | cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:* | ||
>= 1.9.0, < 1.9.5CPE matchmatch criteria | cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.
istio/istio: authorization bypass when using AUTO_PASSTHROUGH
May 11, 2021Istio AUTO_PASSTHROUGH authorization bypass (CVE-2021-31921)
Istio AUTO_PASSTHROUGH authorization bypass vulnerability (CVE-2021-31921)