Critical severity · published Jun 2, 2021
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…
9.8
CVSS
1.5%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.5% · higher than 73% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
IS
Istio · Istio
before 1.8.6; 1.9.0 before 1.9.5 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-31921
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-31921
Exploit
https://istio.io/latest/news/security/istio-security-2021-006/
More from Istio
9.8
CVE-2026-111497
Out-of-Bounds Write in Google Brotli Decoder
9.8
CVE-2022-31045
Istio is an open platform to connect, manage, and secure microservices
9.8
CVE-2022-21679
Istio is an open platform to connect, manage, and secure microservices
8.8
CVE-2022-21701
Istio is an open platform to connect, manage, and secure microservices
8.8
CVE-2021-34824
Istio (1.8.x, 1.9.0-1.9.5 and 1.10.0-1.10.1) contains a remotely exploitable vulnerability where credentials specified in the Gateway and DestinationRule credentialName field can…