Token disclosure and open redirect via unchecked ncu
Published Sep 16, 2026 · Updated Sep 16, 2026
Open redirect in Newsletter before 9.3.7 allows remote attackers to send users to external sites through a public subscription request. The subscription handler accepts confirm_url or ncu as the post-subscription destination without restricting it to the local site and exposes the subscriber token in the redirect. No account is required; the token permits front-end actions on the affected subscriber record.
Summary
What happened
Open redirect in Newsletter before 9.3.7 allows remote attackers to send users to external sites through a public subscription request. The subscription handler accepts confirm_url or ncu as the post-subscription destination without restricting it to the local site and exposes the subscriber token in the redirect. No account is required; the token permits front-end actions on the affected subscriber record.
The record
- CVE
- CVE-2026-86823
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Vendor
- Stefano Lissa & The Newsletter Team
- Product
- Newsletter
- Classifications
- T1566.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 16, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <9.3.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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