Lack of input validation in Mailerup input parameter leads to Open Redirect
Summary
| CVE | CVE-2026-13163 |
|---|---|
| State | PUBLISHED |
| Assigner | Secur0 |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-24 13:16:31 UTC |
| Updated | 2026-06-25 19:58:30 UTC |
| Description | Open redirect vulnerability (CWE-601) in the _safe_redirect function of the click-tracking endpoint (/c/<token>/) in Mailerup <1.0.0 on all platforms allows remote unauthenticated attackers to redirect victims to arbitrary external sites and conduct phishing attacks via a crafted u query parameter, because the URL scheme is validated (blocking javascript: and data:) but the destination host is not restricted to an allowlist, and a signing.BadSignature exception is silently caught so a valid signed token is not required. |
Risk And Classification
Primary CVSS: v4.0 5.3 MEDIUM from 4daa8cea-433a-44bd-9456-53b127fc289a
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/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
EPSS: 0.003290000 probability, percentile 0.246810000 (date 2026-06-29)
Problem Types: CWE-601 | CWE-601 CWE-601 URL redirection to untrusted site ('open redirect')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 4daa8cea-433a-44bd-9456-53b127fc289a | Secondary | 5.3 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 5.3 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N |
CVSS v4.0 Breakdown
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/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
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/Maalfer/mailerup/commit/99eb6d4586134bf3f4422093fbf47d6794ef0ee5 | 4daa8cea-433a-44bd-9456-53b127fc289a | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Dario Rivas Quero from Secur0 security team (en)
CNA: Cristian Fernandez Cornejo from Secur0 security team (en)
CNA: Mario Alvarez Fernandez (en)
CNA: Xoan M. Otero Jorge (en)
CNA: Secur0 CNA (en)
Additional Advisory Data
Solutions
CNA: Upgrade to version 1.0.1 or higher.