Server-Side Request Forgery Vulnerability in Heym Product by Heymrun
CVE-2026-100858

7.6HIGH

Key Information:

Vendor

Heymrun

Status
Heym
Vendor
CVE Published:
27 September 2026

What is CVE-2026-100858?

Heym versions prior to 0.0.109 are vulnerable to a server-side request forgery (SSRF) attack through Slack, Discord, and Crawler workflow nodes. These nodes can send HTTP requests to user-defined URLs via credentials, exploiting an inadequately secured HTTP client. This vulnerability allows any registered user to configure a credential that targets internal network addresses, enabling the execution of workflows that communicate with private or loopback endpoints, thus disclosing sensitive data. The issue arises from a lack of robust validation in the credential API, which only checks for non-empty URLs. As a result, attackers can manipulate workflows to reveal sensitive backend responses.

Affected Version(s)

heym 0 < 0.0.109

heym 0.0.109

References

https://github.com/heymrun/heym/security/advisories/GHSA-...
vendor-advisory
https://www.vulncheck.com/advisories/heym-before-0.0.109-...
third-party-advisory

CVSS V4

Score:
7.6
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

unbengable12
mbakgun
.