CVE-2026-100865

Heym before 0.0.53 Remote Code Execution via eval() Sandbox Escape

Published Sep 27, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

Description

Heym before 0.0.53 evaluates workflow condition expressions using Python's eval() with insufficient sandboxing in the workflow executor service. Authenticated users can edit workflow condition nodes or import malicious templates to execute arbitrary Python and OS commands as the backend process user.

Analysis

Technical impact

Heym before 0.0.53 evaluates workflow condition expressions using Python's eval() without sufficient sandboxing in the workflow executor service. Authenticated users can edit workflow condition nodes or import malicious templates, enabling them to execute arbitrary Python and OS commands as the backend process user. This flaw provides remote code execution with full system privileges.

Affected Systems

The vulnerabilities affect all instances of the Heym application running any release before 0.0.53, including versions 0.0.0 through 0.0.52. Users of these versions should verify the application level and any custom workflow definitions for the exposed conditions and webhook configurations.

Risk and Exploitability

The CVSS score of 8.7 indicates high severity, and the EPSS score is <1%, showing a low probability of exploitation at present. The vulnerability is not listed in the CISA KEV catalog. Based on the description, the likely attack vector is a remote actor who can edit workflow condition nodes or import malicious templates via an authenticated session. By triggering the vulnerable eval(), the attacker can execute arbitrary Python and OS commands as the backend process user, potentially compromising the entire system.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

heymrun

heym

unaffected

Version	Status	Constraints
`0`	affected	< 0.0.53
`0.0.53`	unaffected	—

No data.

Vendor Product Versions

Heymrun

Heym

Version	Status	Scheme	Platform
`[0,0.0.53)`	affected	semver	—
`0.0.53`	unaffected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the latest heym release (0.0.53 or later) to remove the eval() vulnerability.
Restrict workflow condition node editing to users with administrative privileges or enforce strict input validation for condition expressions.
Monitor workflow execution logs for suspicious activity that may indicate unauthorized code execution.

Generated by OpenCVE AI on September 27, 2026 at 17:28 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.399% probability within 30 days)

Exploitation poc

Automatable no

Technical Impact total

References

Link	Providers
https://github.com/heymrun/heym/commit/341d1012367cd74f85c617e1c98dd49e3fcb5e83
https://github.com/heymrun/heym/security/advisories/GHSA-pm6h-x3h5-j38h

History

Sep 29, 2026 4:15 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Sep 27, 2026 5:30 PM References updated View changes

Type	Values Removed	Values Added
References	https://www.vulncheck.com/advisories/heym-before-0.0.53-multiple-rce-and-authentication-bypass-vulnerabilities

Sep 27, 2026 4:45 PM Description updated. Title updated. Added references View changes

Type	Values Removed	Values Added
Description	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.	Heym before 0.0.53 evaluates workflow condition expressions using Python's eval() with insufficient sandboxing in the workflow executor service. Authenticated users can edit workflow condition nodes or import malicious templates to execute arbitrary Python and OS commands as the backend process user.
Title	Heym before 0.0.53 Multiple RCE and Authentication Bypass Vulnerabilities	Heym before 0.0.53 Remote Code Execution via eval() Sandbox Escape
References		https://github.com/heymrun/heym/commit/341d1012367cd74f85c617e1c98dd49e3fcb5e83

Sep 27, 2026 4:30 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Heymrun Heymrun heym
Vendors & Products		Heymrun Heymrun heym

Sep 27, 2026 2:00 AM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		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.
Title		Heym before 0.0.53 Multiple RCE and Authentication Bypass Vulnerabilities
Weaknesses		CWE-94
References		https://github.com/heymrun/heym/security/advisories/GHSA-pm6h-x3h5-j38h https://www.vulncheck.com/advisories/heym-before-0.0.53-multiple-rce-and-authentication-bypass-vulnerabilities
Metrics		cvssV3_1 `{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}` cvssV4_0 `{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}`