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5.0
Istio: Sensitive Data Leaked to Envoy Proxies via Internal Service Request
GHSA-fgw5-hp8f-xfhc
Summary
Istio's internal service request feature can leak sensitive data to Envoy proxies if an internal service is used as a JWT key source. This happens when Istio makes an unauthenticated request to the internal service, potentially exposing sensitive info. To fix, update to Istio version 1.29.2 or 1.28.6, or implement a validating admission policy to block suspicious key source URLs.
What to do
- Update istio.io istio to version 0.0.0-20260410004459-189832a289c1.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| go | istio.io | istio |
< 0.0.0-20260410004459-189832a289c1 Fix: upgrade to 0.0.0-20260410004459-189832a289c1
|
Original title
Istio: SSRF via RequestAuthentication jwksUri
Original description
### Impact
When a RequestAuthentication resource is created with a jwksUri pointing to an internal service, istiod makes an unauthenticated HTTP GET request to that URL without filtering out localhost or link local ips. This can result in sensitive data being distributed to Envoy proxies via xDS configuration.
Note: a partial mitigation for this was released in 1.29.1, 128.5, and 1.27.8; however, it was incomplete and missed a few codepaths. 1.29.2 and 1.28.6 contain the more robust fix.
### Patches
_Has the problem been patched? What versions should users upgrade to?_
### Workarounds
Users can deploy a `ValidatingAdmissionPolicy` to prevent the creation of `RequestAuthentication` resources with suspicious jwksUri field values (e.g. localhost, 127.0.0.0/8, 169.254.0.0/16, the ipv6 variants, etc.).
### References
None
When a RequestAuthentication resource is created with a jwksUri pointing to an internal service, istiod makes an unauthenticated HTTP GET request to that URL without filtering out localhost or link local ips. This can result in sensitive data being distributed to Envoy proxies via xDS configuration.
Note: a partial mitigation for this was released in 1.29.1, 128.5, and 1.27.8; however, it was incomplete and missed a few codepaths. 1.29.2 and 1.28.6 contain the more robust fix.
### Patches
_Has the problem been patched? What versions should users upgrade to?_
### Workarounds
Users can deploy a `ValidatingAdmissionPolicy` to prevent the creation of `RequestAuthentication` resources with suspicious jwksUri field values (e.g. localhost, 127.0.0.0/8, 169.254.0.0/16, the ipv6 variants, etc.).
### References
None
ghsa CVSS3.1
5.0
Vulnerability type
CWE-918
Server-Side Request Forgery (SSRF)
Published: 16 Apr 2026 · Updated: 16 Apr 2026 · First seen: 16 Apr 2026