CVE-2026-39350

CVE-2026-39350 is a medium-severity security vulnerability in istio.io/istio (go), affecting versions >= 0.0.0-20241024090207-0bf27d49ba4b, < 0.0.0-20260403004500-692e460c342d. It is fixed in 0.0.0-20260403004500-692e460c342d.

Summary

Workarounds

None

Impact

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 SA e.g. cert-manager.io also matches cert-manager-io, cert-managerXio, etc. A DENY rule targeting the same name fails to block those variants.

CVE-2026-39350 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.0-20260403004500-692e460c342d); upgrading removes the vulnerable code path.

Affected versions

istio.io/istio (>= 0.0.0-20241024090207-0bf27d49ba4b, < 0.0.0-20260403004500-692e460c342d)

Security releases

istio.io/istio → 0.0.0-20260403004500-692e460c342d (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

See it in your environment

Remediation advice

Fixes are available in 1.29.2, 1.28.6, and 1.27.9

Frequently Asked Questions

  1. What is CVE-2026-39350? CVE-2026-39350 is a medium-severity security vulnerability in istio.io/istio (go), affecting versions >= 0.0.0-20241024090207-0bf27d49ba4b, < 0.0.0-20260403004500-692e460c342d. It is fixed in 0.0.0-20260403004500-692e460c342d.
  2. How severe is CVE-2026-39350? CVE-2026-39350 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which versions of istio.io/istio are affected by CVE-2026-39350? istio.io/istio (go) versions >= 0.0.0-20241024090207-0bf27d49ba4b, < 0.0.0-20260403004500-692e460c342d is affected.
  4. Is there a fix for CVE-2026-39350? Yes. CVE-2026-39350 is fixed in 0.0.0-20260403004500-692e460c342d. Upgrade to this version or later.
  5. Is CVE-2026-39350 exploitable, and should I be worried? Whether CVE-2026-39350 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-39350 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-39350? Upgrade istio.io/istio to 0.0.0-20260403004500-692e460c342d or later.

Other vulnerabilities in istio.io/istio

CVE-2026-39350CVE-2022-31045CVE-2019-18817CVE-2019-14993CVE-2022-23635

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