Miniflux 2 is an open source feed reader. Prior to 2.3.1, IsRelativePath in internal/urllib/url.go accepts redirect targets containing backslashes because Go URL parsing treats them as path characters. Browser backslash normalization converts them to forward slashes. An unauthenticated attacker can provide such a redirect_url value to the login flow, bypass the relative-path and host checks, and redirect a victim to an attacker-controlled external site. This issue is fixed in version 2.3.1.
https://github.com/miniflux/v2/security/advisories/GHSA-m999-j542-5w3r
https://github.com/miniflux/v2/releases/tag/2.3.1
https://github.com/miniflux/v2/pull/4362
https://github.com/miniflux/v2/commit/c896bafdaa19c3f280b02b1059f84706495f1949
Published: 2026-08-21
Updated: 2026-08-21
Base Score: 5.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 6.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 5.1
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00432