CVE-2026-100858 json
heym before 0.0.109 Server-Side Request Forgery via Workflow Nodes
published last mo. modified last mo. also EUVD-2026-87823
- cvss
- 6.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 27%
- public exploits
- 0
- none known
Summary
heym before 0.0.109 contains a server-side request forgery vulnerability in the Slack, Discord, and Crawler workflow nodes. These nodes issue HTTP requests to URLs taken from user-created credentials (webhook_url / flaresolverr_url) using an unguarded HTTP client, bypassing the SSRF egress guard that already protects the HTTP, WebSocket, and MCP nodes; the credential API validates only that the URL is non-empty. Any registered user can create a credential pointing at an internal address and execute a workflow, causing the backend to reach loopback, private, link-local, or cloud-metadata endpoints and return the full response body in the node output (non-blind SSRF).
Patch / fix
- heymrun heym 0.0.109
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Check with FencerCISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- last mo.
Exploit prediction
0.34% chance of exploitation in the next 30 days, higher than 27% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- github.com https://github.com/heymrun/heym/security/advisories/GHSA-39j3-6x3x-8rcr referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 7.6 | CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N |
| CNA | 3.1 | 6.8 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N |
| CNA | 4.0 | 7.6 | CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- heymrun heym
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/heymrun/heym/security/advisories/GHSA-39j3-6x3x-8rcr
vendor-advisory, exploit
-
vulncheck.com
/advisories/heym-before-0.0.109-server-side-request-forgery-via-workflow-nodes
third-party-advisory
Sources
- CVE List CVE-2026-100858
- NVD CVE-2026-100858
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