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Potential Authentication bypass with CookieAuthenticator

Critical
markstory published GHSA-h7xh-9h2x-2m37 Aug 21, 2026

Package

composer cakephp/authentication (Composer)

Affected versions

<2.11.2
>3.0.0, <3.3.7
>4.0.0, <4.2.1

Patched versions

2.11.2
3.3.7
4.2.1

Description

Impact

If the CookieAuthenticator authentication is not encrypted it is vulnerable to authentication bypass, and potential CPU/memory exhaustion through forged tokens.

Patches

2.11.2, 3.3.7, 4.2.1 contain a fix for this issue. These releases introduce a new cookie format with backwards compatibility for existing token data. The compatibility for existing tokens can be disabled by setting legacyTokens = false when configuring a CookieAuthenticator.

Workarounds

Enable EncryptedCookieMiddleware with CookieAuth (or your cookie name).

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

CVE ID

CVE-2026-77337

Weaknesses

Authentication Bypass by Spoofing

This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. Learn more on MITRE.

Allocation of Resources Without Limits or Throttling

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. Learn more on MITRE.

Credits