How severe is CVE-2026-39350?

CVE-2026-39350 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-39350 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39350?

CVE-2026-39350 affects Istio. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39350?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-39350 have an EU (EUVD) identifier?

Yes. CVE-2026-39350 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23128.

When was CVE-2026-39350 published?

CVE-2026-39350 was published on 2026-04-15 and last updated on 2026-06-17.

CVE-2026-39350

CVE-2026-39350 is a medium-severity vulnerability in Istio with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-185.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-23128
Weakness: CWE-185
Affected product: Istio
Published: 2026-04-15
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-39350?: 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.
How severe is CVE-2026-39350?: CVE-2026-39350 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-39350 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39350?: CVE-2026-39350 affects Istio. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39350?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-39350 have an EU (EUVD) identifier?: Yes. CVE-2026-39350 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23128.
When was CVE-2026-39350 published?: CVE-2026-39350 was published on 2026-04-15 and last updated on 2026-06-17.

References

https://github.com/istio/istio/security/advisories/GHSA-9gcg-w975-3rjh

Affected products (1)

cpe:2.3:a:istio:istio:*:*:*:*:*:*:*:*

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