IBM discloses high-severity identity-replay flaw in ContextForge MCP Gateway

GitHub published a high-severity advisory for IBM's ContextForge MCP Gateway on November 14, 2026, warning that attackers can replay identity-propagation signatures and expose user identity data to third-party MCP servers.

GitHub Security Advisories published a high-severity vulnerability disclosure for IBM's ContextForge MCP Gateway on November 14, 2026, one day after IBM disclosed six medium-severity flaws in the same product. The advisory, CVE-2026-110278, carries a CVSS score of 7.4 and lets attackers replay identity-propagation claim signatures or expose user identity data to third-party MCP servers.

What the advisory covers

CVE-2026-110278 was published on November 14, 2026 with a CVSS score of 7.4 (High).
The flaw affects IBM ContextForge MCP Gateway versions 1.0.0 through 1.1.0.
It is classified as CWE-294, Authentication Bypass by Capture-Replay.
Static signature payloads combined with missing per-gateway configuration checks during tool invocation let an attacker replay identity-propagation claim signatures.
The flaw can expose sensitive user identity information to third-party MCP servers behind the gateway.
This CVE is distinct from the six medium-severity ContextForge MCP Gateway CVEs IBM disclosed on November 13, 2026.

What it means for AI builders

The back to back disclosures show how exposed identity-propagation flows are in enterprise MCP deployments: a gateway meant to broker identity between an application and third-party MCP servers can itself become the weak link if signature payloads can be captured and replayed. For teams running ContextForge MCP Gateway to connect AI agents to external tools, the flaw means user identity data could reach MCP servers it was never meant to reach, which raises the pressure to patch quickly.

Fix and availability

IBM ships the fix in version 1.1.1, which makes signature payloads dynamic by adding nonces and timestamps so a captured signature cannot be replayed later. Operators running ContextForge MCP Gateway 1.0.0 through 1.1.0 should upgrade to 1.1.1.

Sources

CVE-2026-110278 (GitHub Security Advisories, November 14, 2026, official)

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