CVE-2026-79749 samanhappy CVE debrief

Who should care

MCPHub users and administrators should assess exposure and apply patches to prevent potential SSRF attacks. The vulnerability allows an attacker to bypass the SSRF guard using IPv6 transition addresses, potentially leading to unauthorized access to internal infrastructure. Defenders should verify their exposure, apply patches, and monitor for suspicious activity. The custom isBlockedIpv6 function in src/utils/ssrf.ts did not check for IPv6 transition

Why it matters

CVE-2026-79749 MCPHub SSRF guard bypass vulnerability requires immediate attention from MCPHub users and administrators. The vulnerability allows an attacker to bypass the SSRF guard using IPv6 transition addresses, potentially leading to unauthorized access to internal infrastructure. Defenders should verify their exposure, apply patches, and monitor for suspicious activity.

• Potential unauthorized access to internal infrastructure
• Possible data breaches or lateral movement
• Need for verification of affected versions and scope
• Priority for patching and monitoring

Technical summary

MCPHub's SSRF guard bypass vulnerability via IPv6 transition addresses (CVE-2026-79749). The custom isBlockedIpv6 function in src/utils/ssrf.ts did not check for IPv6 transition address families, allowing an attacker to encode a private IPv4 address inside these IPv6 forms to bypass the SSRF guard and reach internal infrastructure. The vulnerability allows an attacker to bypass the SSRF guard using IPv6 transition addresses, potentially leading to unauthorized access to internal infrastructure. Defenders should verify their exposure, apply patches, and monitor for suspicious activity (520

Defensive priority

High priority for MCPHub users and administrators

Recommended defensive actions

• Review and apply patch version 1.0.32
• Verify MCPHub server configurations for potential exposure
• Monitor for suspicious URL encoding attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but the scope of affected versions and potential impact require verification from official sources. The vulnerability allows an attacker to bypass the SSRF guard using IPv6 transition addresses, potentially leading to unauthorized access to internal infrastructure. Defenders should verify their exposure, apply patches, and monitor for suspicious activity. The custom isBlockedIpv6 function in src/utils/ssrf.ts did not check for IPv6 transition address families, allowing

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.