Istio: AuthorizationPolicy serviceAccounts regex injection via unescaped dotsGHSA-9gcg-w975-3rjh
MEDIUMFix: istio/istio@692e460GHSA-9gcg-w975-3rjh is a medium-severity (CVSS 5.4) CWE-185 vulnerability in istio.io/istio. A fix is available for istio.io/istio — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-9gcg-w975-3rjh.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
istio.io/istioReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | istio.io/istio | ≥ 0.0.0-20241024090207-0bf27d49ba4b&&< 0.0.0-20260403004500-692e460c342d | 0.0.0-20260403004500-692e460c342dgo get istio.io/istio@v0.0.0-20260403004500-692e460c342d |
Affected Products
istioistioDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for istio.io/istio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update istio.io/istio to 0.0.0-20260403004500-692e460c342d or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9gcg-w975-3rjh is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
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…
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.Source: Red Hat security advisory for GHSA-9gcg-w975-3rjh (CC BY 4.0)
Frequently Asked Questions
Is GHSA-9gcg-w975-3rjh in your dependencies?
Find it across Go, including transitive dependencies.