---
cve: "CVE-2026-75833"
severity: "HIGH"
cvss: 8.6
epss: "19%"
vendor: "getgrav"
kev: false
exploited: false
published: "2026-08-18 12:19:33"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-06T03:37:30+02:00"
---

# CVE-2026-75833

> 8.6 HIGH · 🧪 PoC

## Beschreibung

The Grav API plugin (getgrav/grav-plugin-api, bundled with Grav 2.0's admin-next/API stack) before version 1.0.14 contains an open redirect weakness in SsoController::sanitizeReturnTo(). The function rejects a literal '//' prefix but does not account for browsers normalizing backslashes to slashes in special (http/https) schemes, so a returnTo value such as '/\evil.com' passes the guard and is later resolved by the browser as the protocol-relative URL '//evil.com'. Following a legitimate OAuth login flow, an attacker-supplied returnTo parameter could redirect an authenticated victim to an attacker-controlled site for post-login phishing. Full browser-side exploitability depends on the admin-next SPA's client-side oauth-callback handler and was not independently verified by the reporter.

## CVSS-Vektor

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

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

## Referenzen

- <https://github.com/getgrav/grav/security/advisories/GHSA-x72c-4jc4-8rh6>
- <https://www.vulncheck.com/advisories/grav-api-plugin-open-redirect-via-backslash-bypass>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-75833) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_