CVE-2026-13163: medium-severity vulnerability in Mailerup
Lack of input validation in Mailerup input parameter leads to Open Redirect
Published
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.5%
exploitation probability
0.5%top 58% of all CVEs
observed exploitation
nono source reports it
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.
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
Affected products
Mailerup · MailerupRelated CVEs — Mailerup
In the same product, most dangerous first.