CVE-2026-56695: OpenHarness ohmo Gateway Unauthorized Snapshot Access via Default Remote Invocation

Technical summary

The vulnerability stems from the remote_invocable parameter defaulting to True for the /resume and /summary slash commands in OpenHarness ohmo gateway. This default configuration permits any admitted sender on a shared channel to invoke snapshot enumeration and loading operations without additional authorization checks. The attack surface includes any environment where multiple users share gateway channel access and snapshots are not isolated by role or ownership. CWE-862 (Missing Authorization) categorizes the underlying defect: the application fails to enforce object-level access controls on snapshot retrieval.

Business impact

Organizations using OpenHarness ohmo gateway for multi-user or team-based workflows face exposure of confidential information stored within session snapshots. Leaked credentials could enable lateral movement or privilege escalation within downstream systems. Exposed system prompts may reveal business logic, API integrations, or proprietary tool configurations. For regulated environments (healthcare, finance, legal), unauthorized access to snapshots containing client data or sensitive processing results creates compliance risk and potential breach notification obligations.

Affected systems

OpenHarness ohmo gateway instances with the /resume and /summary commands enabled are affected. The vulnerability applies to any deployment where multiple users share gateway channel access and session snapshots are stored. No specific product version range is provided in vendor advisories at this time; verify affected versions against OpenHarness release notes and security announcements.

Exploitability

Exploitation requires prior authentication to the gateway—an attacker cannot perform this attack from an unauthenticated state. However, the barrier to entry is low for insiders or users with legitimate (but limited) access to shared channels. Snapshot enumeration is trivial once access is obtained, as attackers need only iterate snapshot IDs or use common naming patterns. The CVSS 3.1 score of 6.5 (MEDIUM) reflects the requirement for authenticated access (PR:L) balanced against high confidentiality impact and network-based attack vector.

Remediation

Administrators should immediately audit gateway configurations and set remote_invocable to False for /resume and /summary commands unless explicitly required. Where remote invocation is necessary, implement explicit authorization policies that bind snapshot access to ownership or explicit role assignments. Additionally, review historical snapshot access logs to identify any unauthorized enumeration or retrieval during the vulnerability window. Consider enforcing channel-level access controls and segmenting user populations by sensitivity of data stored in snapshots.

Patch guidance

Check OpenHarness security advisories and release notes for patched versions that correct the default remote_invocable setting. Apply patches to all gateway instances in your environment. If patching cannot be completed immediately, apply the manual configuration workaround: disable remote invocation for these commands via gateway configuration files or environment variables, then verify the changes are in effect by testing unauthorized snapshot access attempts.

Detection guidance

Monitor gateway logs for repeated /resume or /summary command invocations with different snapshot IDs originating from the same user or session—a pattern consistent with enumeration. Alert on snapshot loads where the requesting user does not match the snapshot owner. Implement audit logging of all snapshot access and correlation of access patterns across your gateway instances. Review recent snapshot loads by privilege level to identify cross-user access anomalies.

Why prioritize this

Although this vulnerability requires prior authentication, the low effort required to exploit it post-authentication, combined with exposure of high-value information (credentials, prompts, file paths), warrants prompt remediation. The risk is amplified in environments with shared gateway channels or federated access models. Organizations should treat remediation as near-term priority, especially in regulated industries or where gateways process sensitive workloads.

Risk score, explained

The CVSS 3.1 score of 6.5 reflects a MEDIUM severity assessment: network-accessible endpoint, low attack complexity (no special conditions required once authenticated), authenticated attacker required, and high confidentiality impact with no integrity or availability impact. The score appropriately captures the insider-threat and lateral-access risk but is constrained by the authentication requirement. Real-world risk in your environment may be higher if your gateway user population is large or includes contractors with temporary access.

Frequently asked questions