DNS Rebinding Affecting rmcp 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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Test your applications- Snyk IDSNYK-RUST-RMCP-16599166
- published9 May 2026
- disclosed6 May 2026
- creditJLLeitschuh
Introduced: 6 May 2026
NewCVE-2026-42559 (opens in a new tab)How to fix?
Upgrade rmcp to version 1.4.0 or higher.
Overview
Affected versions of this package are vulnerable to DNS Rebinding via the Host header validation process. An attacker can gain unauthorized access to internal resources and potentially execute arbitrary code by convincing a user to visit a malicious website, which then sends authenticated requests to a server running on a private or loopback interface through a DNS rebinding attack.
Workaround
This vulnerability can be mitigated by placing the server behind a reverse proxy configured to reject requests with unexpected Host headers, or by avoiding binding the server to 0.0.0.0 without such a proxy.