1.25.5-patch5

Solo build of Istio version 1.25.5-patch5 patch release.

This release note describes what’s different between Solo builds of Istio versions 1.25.5-patch4 and 1.25.5-patch5.

Security Notice

Envoy CVEs

• CVE-2026-26308: (CVSS score 7.5, High): Fixed RBAC header matcher to validate each header value individually instead of concatenating multiple header values into a single string. This prevents potential bypasses when requests contain multiple values for the same header.
• CVE-2026-26311: (CVSS score 5.9, Medium): Fixed an issue where filter chain execution could continue on HTTP streams that had been reset but not yet destroyed, potentially causing use-after-free conditions.
• CVE-2026-26310: (CVSS score 5.9, Medium): Fixed a crash in Utility::getAddressWithPort when called with a scoped IPv6 address (e.g., fe80::1%eth0).
• CVE-2026-26309: (CVSS score 5.3, Medium): Fixed an off-by-one write in JsonEscaper::escapeString() that could corrupt the string null terminator.

Istio CVEs

The following security fixes were backported:

• CVE-2026-31838 / GHSA-974c-2wxh-g4ww: (CVSS score 6.9, Medium): Debug Endpoints Allow Cross-Namespace Proxy Data Access.
• CVE-2026-31837 / GHSA-v75c-crr9-733c: (CVSS score 8.7, High): JWKS Resolver Failure May Allow Authentication Bypass Using Known Default Keys.

Other Istio Security Fixes

The following security fixes were backported:

• Fixed XDS debug endpoints on plaintext port 15010 to require authentication, preventing unauthenticated access to proxy configuration.
• Fixed potential SSRF in WasmPlugin image fetching by validating bearer token realm URLs.
• Fixed HTTP debug endpoints on port 15014 to enforce namespace-based authorization, preventing cross-namespace proxy data access.

Solo Flavor Changes

No changes in this section.

FIPS Flavor Changes

No changes in this section.