What’s Vulnerable › Vulnerabilities
CVE-2026-39350: Istio AuthorizationPolicy Incorrect Regex Matching of Dots in serviceAccounts Fields Allows Policy Bypass
- Severity: medium (CVSS 5.4 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-15 · updated 2026-06-17
- Weakness: CWE-185
Description
Istio is an open platform to connect, manage, and secure microservices. In versions 1.25.0 through 1.27.8, 1.28.0 through 1.28.5, 1.29.0, and 1.29.1, the serviceAccounts and notServiceAccounts fields in AuthorizationPolicy incorrectly interpret dots (.) as a regular expression matcher. Because . is a valid character in a service account name, an AuthorizationPolicy ALLOW rule targeting a service account such as cert-manager.io also matches cert-manager-io, cert-managerXio, etc. A DENY rule targeting the same name fails to block those variants. Fixes are available in versions 1.29.2, 1.28.6, and 1.27.9.
Affected products
- istio: from 1.25.0 before 1.27.9; from 1.28.0 before 1.28.6; from 1.29.0 before 1.29.2 — fixed in 1.27.9, 1.28.6, 1.29.2
How to fix
Upgrade to a fixed version: istio 1.27.9, 1.28.6, 1.29.2. Check the vendor advisory for mitigations.
References
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