Insecure Default Initialization of Resource Affecting github.com/modelcontextprotocol/go-sdk/internal/util package, versions <1.4.0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published2 Apr 2026
- disclosed1 Apr 2026
- creditJonathan Leitschuh
Introduced: 1 Apr 2026
CVE-2026-34742 (opens in a new tab)How to fix?
Upgrade github.com/modelcontextprotocol/go-sdk/internal/util to version 1.4.0 or higher.
Overview
Affected versions of this package are vulnerable to Insecure Default Initialization of Resource due to DNS rebinding protection being disabled by default in HTTP-based servers using StreamableHTTPHandler or SSEHandler. An attacker can access internal resources or invoke tools exposed by the local server by exploiting DNS rebinding through a malicious website.
Note:
This is only exploitable if the server is running on localhost without authentication.