Punk::OAuth2 versions before 0.03 for Perl allow an attacker-chosen off-site redirect after login because same_origin_path accepts a backslash or tab in the return parameter

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-75628
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-20 01:16:53 UTC
Updated2026-08-20 03:16:23 UTC
DescriptionPunk::OAuth2 versions before 0.03 for Perl allow an attacker-chosen off-site redirect after login because same_origin_path accepts a backslash or tab in the return parameter. oauth2_login reads the return parameter from the initiation request, runs same_origin_path over it, and stores the survivor in the session flow record as the post-login redirect target. That check rejects a value that does not begin with a slash, one with a slash as its second byte, and one containing CR or LF. A backslash and a tab pass. The URL Standard treats a backslash as equivalent to a slash for special schemes, so `/\evil.example` parses with the authority `evil.example`. It also strips ASCII tab before parsing, so a tab between two leading slashes leaves `//evil.example`. A crafted link to the application's own login route lands the victim on the attacker's site after a genuine authentication. The redirect carries no authorization code or access token.

Risk And Classification

EPSS: 0.002600000 probability, percentile 0.179110000 (date 2026-08-20)

Problem Types: CWE-601 | CWE-601 CWE-601 URL Redirection to Untrusted Site ('Open Redirect')

References

ReferenceSourceLinkTags
url.spec.whatwg.org 9b29abf9-4ab0-4765-b253-1875cd9b441e url.spec.whatwg.org
datatracker.ietf.org/doc/html/rfc9700 9b29abf9-4ab0-4765-b253-1875cd9b441e datatracker.ietf.org
url.spec.whatwg.org 9b29abf9-4ab0-4765-b253-1875cd9b441e url.spec.whatwg.org
metacpan.org/release/LNATION/Punk-OAuth2-0.03/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
metacpan.org/release/LNATION/Punk-OAuth2-0.02/source/include/pox/pox_util.h 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
www.openwall.com/lists/oss-security/2026/08/20/1 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to Punk-OAuth2 0.03 or later.

Workarounds

CNA: For deployments that cannot upgrade to 0.03, strip the return query parameter from requests to the oauth2_login initiation route at the reverse proxy. Logins then use the configured redirect_ok destination.

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