Kiwi TCMS account confirmation open redirect through protocol-relative URLs
CVE-2026-77433
Summary In Kiwi TCMS version 16.1, the fix for CVE-2026-54724 (open redirect via unvalidated next parameter) in the account confirmation endpoint is incomplete. The validation uses startswith("/") to check if the redirect URL is local, but this is bypassed by protocol-relative URLs like //evil.com which start with / but redirect the browser to an external attacker-controlled domain. 16.1’s incomplete mitigation still allows protocol-relative destinations and earlier releases lack the mitigation. Vulnerable Code In tcms/kiwiauth/views.py, the Confirm view (line ~113): def getredirecturl(self, args, kwargs): self.url = self.request.GET.get("next", reverse("core-views-index")) if not self.url.startswith("/"): self.url = reverse("core-views-index") The check startswith("/") passes for //evil.com because it begins with /, but browsers interpret //evil.com as a protocol-relative URL that redirects to https://evil.com (or http://evil.com depending on the current page's protocol). Proof of Concept GET /confirm/ /?next=//evil.com/phishing HTTP/1.1 Host: kiwi.example.com Response: HTTP/1.1 302 Found Location: //evil.com/phishing The browser follows the redirect to https://evil.com/phishing.…
Assessment
- CVSS
- 6.1 (v3.1)
- Severity
- Medium
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 9 November 2026
- Last updated
- 9 November 2026
- Affected
- kiwitcms
- Weakness
- CWE-601
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
At the source
References
- https://github.com/kiwitcms/Kiwi/security/advisories/GHSA-gcwf-c25f-p9rv
- https://github.com/kiwitcms/Kiwi/security/advisories/GHSA-hmj5-jm8h-h9fh
- https://github.com/kiwitcms/Kiwi/pull/4458
- https://github.com/kiwitcms/Kiwi/commit/65d8f7c2743d7f06a4fca77c060b9d561f02f948
- https://github.com/kiwitcms/Kiwi/releases/tag/v16.2
- https://github.com/advisories/GHSA-gcwf-c25f-p9rv
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