---
cve: "CVE-2026-100863"
severity: "MEDIUM"
cvss: 5.3
epss: "0.3%"
vendor: "heymrun"
kev: false
exploited: false
published: "2026-09-27 02:17:26"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-10-01T22:50:55+02:00"
---

# CVE-2026-100863

> 5.3 MEDIUM · 🧪 PoC

## Beschreibung

Heym versions 0.0.90 and earlier contain two server-side request forgery (SSRF) egress gaps, both remediated in app/services/ssrf_guard.py in 0.0.91. First, the LLM image-edit input loader (_load_image_bytes) fetched caller-controlled HTTP/HTTPS URLs with a bare httpx.get, applying only a scheme check and bypassing the egress-pinning HTTP client; because the workflow DSL supports "imageInput": "$userInput.body.imageUrl", a webhook or API caller can choose the fetch target when a workflow author uses that expression, allowing requests to loopback, RFC1918, and cloud metadata endpoints. Second, _is_public_address unwrapped only IPv4-mapped IPv6 addresses, so IPv6 transition forms — the NAT64 well-known prefix 64:ff9b::/96, deprecated IPv4-compatible ::x.x.x.x addresses, and 6to4 (2002::/16, classified as globally routable by Python 3.11.0 through 3.11.9) — could carry loopback, RFC1918, link-local, or cloud-metadata IPv4 destinations past both the initial URL validation and the dial-time IP pin. Version 0.0.91 routes the image loader through guard_http_url and the guarded client, evaluates NAT64 and IPv4-compatible addresses by their embedded IPv4 address, and refuses 64:ff9b:1::/48, 6to4, and Teredo (2001::/32) outright.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-09-30 15:24:03
- CNA-CVSS: **5.3** (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 1267b7b6a02f88eb447a5d09057296c4fac54c67 (Commit)

## Referenzen

- <https://github.com/heymrun/heym/security/advisories/GHSA-6rph-qqcv-jqh4>
- <https://www.vulncheck.com/advisories/heym-before-0.0.91-ssrf-via-image-fetching-and-ipv6-validation>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-100863) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_