CVE-2026-78655

Deferred Deferred - Pending Action

Session Replay Bypasses TOTP Rate Limit in Punk::Plugin

Publication date: 2026-08-25

Last updated on: 2026-08-26

Assigner: CPANSec

Description

Punk::Plugin::TOTP versions before 0.05 for Perl allow the second-factor attempt limit to be reset by replaying an earlier session cookie because the challenge route counts failures in the session. The POST handler on challenge_path keeps the failure count as tries inside the totp_pending record in the session, raising it on each rejected code and deleting the pending record once it reaches attempts, five by default. Punk::Session carries the session in a signed cookie unless the application declares a store, and keeps no server-side record, so an earlier value of the same session stays valid until the expiry stamped inside it. A client that saves the cookie before its failed attempts and presents it again gets the pending record back with its counter, and the limit never fires. The replayed record is accepted while its own expiry, pending_ttl seconds from the challenge and 300 by default, has not passed. Sessions declared with a store are not affected: the pending record and its counter then live server-side. The attempt limit does not bound guessing of the second factor, which is left to the per-address rate limit the plugin registers on the same path, 30 requests per 60 seconds.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-25

Last Modified

2026-08-26

Generated

2026-09-15

AI Q&A

2026-08-26

EPSS Evaluated

2026-09-14

NVD

CVE-2026-78655

EUVD

EUVD-2026-66120

Affected Vendors & Products

Vendor	Product	Version / Range
punk	plugin	to 0.05 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-642	The product stores security-critical state information about its users, or the product itself, in a location that is accessible to unauthorized actors.
CWE-307	The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.

Attack-Flow Graph

Executive Summary

This vulnerability affects Punk::Plugin::TOTP versions before 0.05 for Perl. It allows attackers to bypass the second-factor attempt limit by replaying an earlier session cookie. The system tracks failed attempts in a session cookie, but since the cookie is signed and not server-side, an attacker can reuse an old cookie to reset the failure count and continue guessing the second factor without triggering the limit.

Detection Guidance

Detecting this vulnerability requires checking if Punk::Plugin::TOTP versions before 0.05 are in use and if session replay attacks are possible. Inspect Perl application dependencies for Punk::Plugin::TOTP versions below 0.05. Check if sessions are stored server-side or rely on signed cookies without a store.

Impact Analysis

If you use Punk::Plugin::TOTP for two-factor authentication, an attacker could exploit this to repeatedly guess the second factor without being locked out. This increases the risk of unauthorized access to your account or system, as the built-in attempt limit is bypassed by replaying session cookies.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by weakening authentication security. The flaw allows replay attacks on session cookies, which could enable unauthorized access to sensitive data protected by these regulations. Organizations relying on this plugin for two-factor authentication may fail to meet security requirements under GDPR's data protection principles or HIPAA's safeguards for protected health information.

Mitigation Strategies

Upgrade Punk::Plugin::TOTP to version 0.05 or later. Ensure sessions are stored server-side by configuring a session store in the application. Monitor for unusual session cookie reuse or failed TOTP attempts.

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