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Vulnerability · Published Aug 20, 2026 · Assigned by CPANSec

CVE-2026-75628Punk::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

Medium 5.7

In plain English

A medium-severity open redirect in Punk-OAuth2. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities).

Severity (CVSS 3.1)5.7Medium
Exploit odds (30 days)0.5%top 56.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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. 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.

Affected products (as reported)

VendorProductVersions
Punk-OAuth2 0 – before 0.03

Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

References