CVE-2026-12049 – pgAdmin 4: Open redirect in multi-factor authentication flow via unvalidated ‘next’ parameter

CVE ID :CVE-2026-12049

Published : June 18, 2026, 11:37 p.m. | 2 hours, 5 minutes ago

Description :Open redirect in pgAdmin 4’s multi-factor authentication flow. The MFA validate and register endpoints honoured the user-supplied ‘next’ query/form parameter without confirming the target pointed back inside pgAdmin, so an authenticated victim who clicked /mfa/validate?next= — a link typically delivered by phishing — would be sent to an attacker-controlled host directly out of the trusted auth flow.

The defect is a trusted-domain redirect, not a privilege bypass: the attacker gains no read/write access to pgAdmin or the victim’s database, but the redirect launders the attacker’s destination through pgAdmin’s URL, which raises the success rate of credential-phishing follow-on against the victim.

Fix introduces a same-origin _is_safe_redirect_url helper and gates every MFA redirect that consumes user-supplied ‘next’ values through it. The helper allows only relative paths and absolute URLs whose scheme is http(s) and whose host matches the current request host; it rejects external hosts in absolute and protocol-relative form, non-http schemes (javascript:, data:, mailto:), userinfo tricks (http://localhost@attacker/), and backslash variants that some browsers normalize to forward slashes. Unsafe targets fall back to the internal browser index. A dedicated regression test exercises each accept/reject category and the original reporter PoC.

This issue affects pgAdmin 4: from 6.0 before 9.16.

Severity: 5.3 | MEDIUM

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