heymrun Heym up to 0.0.52 Workflow Condition Evaluator eval redirect_uri code injection

Summaryinfo

A vulnerability labeled as very critical has been found in heymrun Heym up to 0.0.52. This vulnerability affects the function eval of the component Workflow Condition Evaluator. Such manipulation of the argument redirect_uri leads to code injection. This vulnerability is listed as CVE-2026-100865. The attack may be performed from remote. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in heymrun Heym up to 0.0.52. Affected by this issue is the function eval of the component Workflow Condition Evaluator. The manipulation of the argument redirect_uri with an unknown input leads to a code injection vulnerability. Using CWE to declare the problem leads to CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Heym before 0.0.53 contains multiple independent vulnerabilities. (1) The workflow condition evaluator uses Python eval() without an effective sandbox, allowing any user who can edit a workflow branch/condition node — or who can import a workflow template containing a malicious condition node — to execute arbitrary Python code as the backend process user when the workflow runs. (2) Slack webhook signature verification and (3) Telegram webhook secret-token verification fail open when the trigger node has no credentialId or an empty signing secret, allowing anyone who knows the public webhook URL to trigger workflows with the owner's credentials without authentication. (4) The OAuth authorization endpoint does not validate the redirect_uri scheme, so an attacker who registers a public OAuth client with a javascript: or data: redirect_uri and lures a victim to the consent screen receives the authorization code and executes attacker-controlled JavaScript in the Heym origin, including access to the victim's HttpOnly auth cookie. (5) WorkflowExecutionToken, PortalSession, HITLRequest.public_token, and OAuthAuthorizationCode values are stored in plaintext, so any database read exposure yields valid scoped bearer tokens, including portal and HITL tokens with a 168-hour TTL that permit workflow execution on behalf of the owner.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-100865 since 09/27/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/27/2026). This vulnerability is assigned to T1059 by the MITRE ATT&CK project.

Upgrading to version 0.0.53 eliminates this vulnerability.

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Productinfo

Vendor

• heymrun

Name

• Heym

Version

• 0.0.1
• 0.0.2
• 0.0.3
• 0.0.4
• 0.0.5
• 0.0.6
• 0.0.7
• 0.0.8
• 0.0.9
• 0.0.10
• 0.0.11
• 0.0.12
• 0.0.13
• 0.0.14
• 0.0.15
• 0.0.16
• 0.0.17
• 0.0.18
• 0.0.19
• 0.0.20
• 0.0.21
• 0.0.22
• 0.0.23
• 0.0.24
• 0.0.25
• 0.0.26
• 0.0.27
• 0.0.28
• 0.0.29
• 0.0.30
• 0.0.31
• 0.0.32
• 0.0.33
• 0.0.34
• 0.0.35
• 0.0.36
• 0.0.37
• 0.0.38
• 0.0.39
• 0.0.40
• 0.0.41
• 0.0.42
• 0.0.43
• 0.0.44
• 0.0.45
• 0.0.46
• 0.0.47
• 0.0.48
• 0.0.49
• 0.0.50
• 0.0.51
• 0.0.52

Website

• Product: https://github.com/heymrun/heym/

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