CyberSecBulletin
CVE-2026-12746NVD status: Deferred

Dancer2::Plugin::Auth::OAuth::Provider: Cross-Site Request Forgery

Published Updated By the CyberSecBulletin desk

CVE-2026-12746 is a high-severity cross-site request forgery vulnerability in Dancer2::Plugin::Auth::OAuth::Provider from BIAFRA, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists version 0.23 as the first without the flaw, so updating Dancer2::Plugin::Auth::OAuth::Provider to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Dancer2::Plugin::Auth::OAuth::Provider to 0.23 or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
BIAFRADancer2::Plugin::Auth::OAuth::Providerbefore 0.230.23

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. Scored by CISA (ADP).

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Cross-Site Request Forgery

The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

How developers prevent this class of flaw

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, use anti-CSRF packages such as the OWASP CSRFGuard. Another example is the ESAPI Session Management control, which includes a component for CSRF.
  • Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
  • Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).

More Cross-Site Request Forgery vulnerabilities (CWE-352)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Cross-Site Request Forgery vulnerabilities

Spotted an error? Tell us.