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OpenHarness CVE-2026-56695

| EUVDEUVD-2026-38467 HIGH
Missing Authorization (CWE-862)
2026-06-23 VulnCheck GHSA-399c-3gm2-p29v
7.1
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Join shared bridged chat channel
  2. Delivery
    Send /resume or /summary with target session ID
  3. Exploit
    Gateway dispatches remote-invocable command
  4. Execution
    Handler loads victim snapshot from workspace store
  5. Persist
    Snapshot contents returned to attacker's channel message
  6. Impact
    Exfiltrate prompts, credentials, and tool output

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires (1) the OpenHarness ohmo gateway to be running and bridged to a remote chat platform such as Slack, (2) the attacker to be an 'admitted' sender on a shared channel/thread bridged to the victim's gateway (PR:L - membership in the shared chat surface, not OpenHarness authentication), and (3) the attacker to know or guess a target session ID, though /resume with no argument also restores the latest session of the targeted runtime. Exploitation is blocked when ohmo gateway is disabled or only used local-UI-only, when no other users share the bridged channel, or after PR #276 is applied (registry sets remote_invocable=False). No user interaction by the victim is required; no MFA or platform-specific build constraints apply.

Impact

The CVSS 4.0 vector AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N indicates a network-reachable, low-complexity attack requiring only low privileges (an 'admitted' gateway sender - typically anyone with access to a shared Slack channel or thread bridged to the gateway), no user interaction, and resulting in high confidentiality impact with no integrity or availability impact, yielding the 7.1 base score. EPSS and CISA KEV status are not provided in the input; given the niche deployment footprint and a same-week disclosure, real-world exploitation is unlikely to be widespread yet, but the bug is trivial to reach for anyone in a shared bridged channel and the patch diff plus VulnCheck advisory effectively document the exploitation steps. Priority should be high for any team running ohmo gateway bridges into multi-tenant chat channels, and low if ohmo is only used in single-user local mode; the description and patch are mutually consistent, so no conflicting signals require vendor confirmation.

Exploit ScenarioDerived

An attacker who shares a Slack channel or thread bridged into a victim's ohmo gateway sends the message '/resume <guessed-or-enumerated-session-id>' and receives the restored conversation contents - including system prompts, tool output, and any secrets the victim pasted - back into the shared channel, or uses '/summary' to obtain a condensed version. The patch's own test case (test_runtime_pool_blocks_registered_resume_without_listing_or_loading_other_sessions) effectively documents the exploit by demonstrating Bob loading Alice's snapshot containing ALICE_PRIVATE_RESUME_SECRET.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Jun 23, 2026

Cross-session information disclosure in HKUDS OpenHarness ohmo gateway allows admitted remote senders to invoke /resume and /summary slash commands, which were incorrectly registered with remote_invocable=True by default, to enumerate and load arbitrary saved session snapshots by ID. Successful exploitation exposes another user's private prompts, credentials, tool outputs, and file paths exchanged through shared gateway channels (e.g. Slack threads). No public exploit identified at time of analysis, but a vendor patch and detailed test cases (PR #276) make the issue easy to weaponize.

RemediationAI

Upstream fix available (PR/commit https://github.com/HKUDS/OpenHarness/pull/276 and commit 92e298852c9b9c8c2266236292073623418c640a); released patched version not independently confirmed, so pull a build that includes that commit from HKUDS/OpenHarness main and redeploy the ohmo gateway. As an interim workaround until the patched build is rolled out, disable the ohmo gateway bridge entirely, or restrict the bridged Slack/chat channels to a single trusted operator so no cross-sender snapshot disclosure is possible - note that this removes the multi-user collaboration use case the gateway is designed for. If you maintain a fork, mirror the fix by registering /resume and /summary with remote_invocable=False and remote_admin_opt_in=True in src/openharness/commands/registry.py; do not attempt to filter by command string at the message layer, as the registry flag is the intended authorization boundary. After patching, rotate any credentials, API keys, or tokens that may have appeared in prior conversation snapshots reachable through the gateway, since prior exposure cannot be ruled out from logs alone.

Affected VersionsENISA

OpenHarness 0 ≤0.1.9

Affected Packages

pypi openharness-ai no fix
euvd openharness no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in pypi, euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

OpenHarness is the HKUDS open-source agent harness; the ohmo subcomponent is a gateway that bridges chat platforms (Slack, etc.) into a local agent runtime. Slash commands are registered through a central SlashCommand registry with a remote_invocable flag that governs whether messages arriving from network-side channels may dispatch the handler. The /summary and /resume control-plane commands were registered without explicitly setting remote_invocable=False, which defaulted them to remotely callable. Because the resume handler accepts a session ID parameter and resolves snapshots from the shared workspace store without scoping by sender_id/channel/session_key, the underlying root cause is CWE-862 (Missing Authorization) on a control-plane primitive that should have been local-UI-only. The fix (commit 92e2988) adds remote_invocable=False and remote_admin_opt_in=True to both registrations, and adds gateway tests asserting that a remote Bob cannot load Alice's snapshot.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 7.1 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 6.5 MEDIUM

Remote over chat bridge with low-privilege admitted-sender membership (PR:L), no user interaction, only confidentiality of other sessions impacted (C:H, I:N, A:N).

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

OpenHarness ohmo gateway /resume and /summary slash commands default remote_invocable to True, allowing admitted remote senders to enumerate and load arbitrary session snapshots by ID. Attackers can exploit this to access victim snapshots containing private prompts, credentials, tool output, and file paths via shared gateway channels.

Blast Radius

ecosystem impact
† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth
  • 1 pypi packages depend on openharness-ai (1 direct, 0 indirect)

Ecosystem-wide dependent count for version 0.1.9.

Executive ViewAI

Why It Matters

HKUDS OpenHarness ohmo gateway's improper access controls on the /resume and /summary endpoints allow remote users to enumerate and load other users' saved session snapshots, exposing stored credentials, private prompts, and sensitive work data shared through gateway channels. No public exploit identified at time of analysis, though vendor-provided test cases create straightforward weaponization path. This affects all organization users interacting through shared gateway channels and creates direct risk of credential compromise and unauthorized data access.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 86% exploitable
Prevalence
Low
niche open-source agent harness with limited production footprint
Threat Intel
1
1 sources
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GHSA GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Partial

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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CVE-2026-6819 HIGH
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Remote attackers can install and activate arbitrary plugins in HKUDS OpenHarness through exposed plugin management comma

CVE-2026-40515 HIGH
8.7 Apr 17

Remote unauthenticated attackers can bypass path restrictions in OpenHarness (pre-commit bd4df81) to read arbitrary sens

CVE-2026-22682 HIGH
8.4 Apr 07

Improper access control in OpenHarness (prior to commit 166fcfe) allows local authenticated attackers with influence ove

CVE-2026-6823 HIGH
8.3 Apr 21

Unauthorized remote access in HKUDS OpenHarness (all versions prior to the PR #147 fix, released as v0.1.7) stems from a

CVE-2026-40516 HIGH
7.8 Apr 17

Server-Side Request Forgery in OpenHarness AI agent framework (pre-commit bd4df81) permits remote unauthenticated attack

CVE-2026-40503 HIGH
7.1 Apr 16

Path traversal in OpenHarness allows authenticated gateway users with chat access to read arbitrary files on the server

CVE-2026-56696 MEDIUM
5.3 Jun 23

Remote prompt injection in OpenHarness allows low-privileged messaging channel participants to persistently corrupt AI a

CVE-2026-6729 MEDIUM
5.3 Apr 20

Session key derivation in HKUDS OpenHarness prior to PR #159 fails to verify sender identity in shared chat/thread scope

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