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TI-2026-11176 Aliases CVE-2026-13163GHSA-wfgr-g7h2-c6m6

Lack of input validation in Mailerup input parameter leads to Open Redirect

Priority LOW 25CWE-601Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Spoofing
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-601.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0051 43rd percentileScored 2026-11-07
Fix Fixed Mailerup (Mailerup): 1.0.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MailerupMailerupbefore 1.0.11.0.1Patch availableCNA
  • Mailerup VendorMailerup Affected before 1.0.1 Fixed in 1.0.1 Patch available CNA

Remediation

  • Fix · CNA Mailerup (Mailerup) Fixed in 1.0.1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Mailerup 1.0.1

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-11177 Unauthenticated self-registration in MailerUp allows access to stored email dataPriority MEDIUM 45
    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-13163
  2. 2026-10-03 Alias added: GHSA-wfgr-g7h2-c6m6

References

Patch 1

  • TI-2026-11177 Unauthenticated self-registration in MailerUp allows access to stored email data CVSS 4.0HIGH 8.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences