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Fencer Vulns
high 8.1

CVE-2026-12746 json

Dancer2::Plugin::Auth::OAuth::Provider versions before 0.23 for Perl do not support the OAuth 2.0 state parameter

published 2026-07-04 4 mo ago modified 2026-10-25 15 d ago also EUVD-2026-41686

cvss
8.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

Dancer2::Plugin::Auth::OAuth::Provider versions before 0.23 for Perl do not support the OAuth 2.0 state parameter.

The authentication_url method builds the provider authorization redirect without issuing a state value, and the callback method exchanges the callback code and registers the resulting token into the session without verifying that the callback corresponds to an authorization request this session initiated.

Any application that uses this plugin for OAuth 2.0 login is exposed to login cross-site request forgery: because the callback is not bound to the session that began the flow, an attacker who starts an authorization with their own provider account can deliver the resulting callback to a victim, causing the victim's session to complete the attacker's authorization and associating the attacker's provider identity and access token with that session. Where the application persists this as an account link, the attacker may retain access to the victim's account through their own provider credentials.

Patch / fix

  • BIAFRA Dancer2::Plugin::Auth::OAuth::Provider 0.23

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
CNA 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

Affected products

  • BIAFRA Dancer2::Plugin::Auth::OAuth::Provider

Classification

Weakness
  • CWE-352 Cross-Site Request Forgery

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.