Uncaught Exception Affecting ecs-service-connect-agent package, versions <0:v1.34.4.2-1.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.54% (43rd percentile)

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  • Snyk IDSNYK-AMZN2023-ECSSERVICECONNECTAGENT-14905605
  • published9 Jan 2026
  • disclosed3 Dec 2025

Introduced: 3 Dec 2025

CVE-2025-64527  (opens in a new tab)
CWE-248  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 ecs-service-connect-agent to version 0:v1.34.4.2-1.amzn2023 or higher.
This issue was patched in ALAS2023-2025-1357.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ecs-service-connect-agent package and not the ecs-service-connect-agent package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, Envoy crashes when JWT authentication is configured with the remote JWKS fetching, allow_missing_or_failed is enabled, multiple JWT tokens are present in the request headers and the JWKS fetch fails. This is caused by a re-entry bug in the JwksFetcherImpl. When the first token's JWKS fetch fails, onJwksError() callback triggers processing of the second token, which calls fetch() again on the same fetcher object. The original callback's reset() then clears the second fetch's state (receiver_ and request_) which causes a crash when the async HTTP response arrives.

CVSS Base Scores

version 3.1