Prevent redirect bypasses via backslash-encoded paths (#36660)#36716
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silverwind merged 1 commit intogo-gitea:release/v1.25from Feb 23, 2026
Merged
Prevent redirect bypasses via backslash-encoded paths (#36660)#36716silverwind merged 1 commit intogo-gitea:release/v1.25from
silverwind merged 1 commit intogo-gitea:release/v1.25from
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This change tightens relative URL validation to reject raw backslashes and `%5c` (encoded backslash), since browsers and URL normalizers can treat backslashes as path separators. That normalization can turn seemingly relative paths into scheme-relative URLs, creating open-redirect risk. Visiting below URL to reproduce the problem. http://localhost:3000/user/login?redirect_to=/a/../\example.com http://localhost:3000/user/login?redirect_to=/a/../%5cexample.com --------- Co-authored-by: silverwind <me@silverwind.io> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com> Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
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Backport #36660 by @lunny
This change tightens relative URL validation to reject raw backslashes and
%5c(encoded backslash), since browsers and URL normalizers can treat backslashes as path separators. That normalization can turn seemingly relative paths into scheme-relative URLs, creating open-redirect risk.Visiting below URL to reproduce the problem.
http://localhost:3000/user/login?redirect_to=/a/../\example.com
http://localhost:3000/user/login?redirect_to=/a/../%5cexample.com