CVE-2026-39350
Description
A flaw was found in Istio, an open platform designed to connect, manage, and secure microservices. The serviceAccounts and notServiceAccounts fields within Istio's AuthorizationPolicy incorrectly interpret dots (.) as a regular expression matcher. This vulnerability allows an attacker to craft service account names that can bypass intended authorization rules. As a result, an ALLOW policy may grant access to unauthorized service accounts, or a DENY policy may fail to block malicious variants, potentially leading to unauthorized access or information disclosure.
Statement
This vulnerability in Istio's AuthorizationPolicy allows for authorization bypass due to incorrect interpretation of dots in service account names. This can lead to unintended access grants or failures in blocking unauthorized service accounts. In Istio service account names may have the '.' character however the AuthorizationPolicy always interpret the '.' as in a regular expression, meaning it'll match any character between the two letters before and after the dot character.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.4 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | Low | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Frequently Asked Questions
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