What’s Vulnerable › Vulnerabilities

CVE-2026-45274: MyBooks: Unauthenticated Registration Bypass via Missing Server-Side ALLOW_REGISTER Enforcement

• Severity: medium (CVSS 6.9 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-19 · updated 2026-09-09
• Weakness: CWE-602

Description

MyBooks is anebook management web server also known as Talebook. In 3.41.2 and earlier, the SignUp.post handler for POST /api/user/sign_up in webserver/handlers/user.py does not enforce the ALLOW_REGISTER configuration flag, even though the frontend hides registration controls when the flag is false. An unauthenticated remote attacker can call the endpoint directly and create a valid account on an instance whose administrator disabled public registration. The process_auth_header function in webserver/handlers/base.py also does not verify the account's active flag, so the newly created and unactivated account can authenticate immediately and access user-level API functionality. The bypass defeats the intended account-creation policy and can supply the low-privilege account required by related authorization vulnerabilities. This issue is fixed in version 3.42.0.

Affected products

• PoxenStudio talebook: before 3.42.0

References

• https://github.com/PoxenStudio/mybooks/commit/a1780c98b00566af7da2fc099fe38500efc02e92
• https://github.com/PoxenStudio/mybooks/releases/tag/3.42.0
• https://github.com/PoxenStudio/mybooks/security/advisories/GHSA-3q85-5vj5-qx5v
• https://github.com/PoxenStudio/mybooks/security/advisories/GHSA-3q85-5vj5-qx5v

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