CVE-2026-33935
Vulnérabilité élevée dans MyTube (franklioxygen)
Description
MyTube is a self-hosted downloader and player for several video websites Prior to version 1.8.72, an unauthenticated attacker can lock out administrator and visitor accounts from password-based authentication by triggering failed login attempts. The application exposes three password verification endpoints, all of which are publicly accessible. All three endpoints share a single file-backed login attempt state stored in `login-attempts.json`. When any endpoint records a failed authentication attempt via `recordFailedAttempt()`, the shared login attempt state is updated, increasing the `failedAttempts` counter and adjusting the associated timestamps and cooldown values. Before verifying a password, each endpoint calls `canAttemptLogin()`. This function checks the shared JSON file to determine whether a cooldown period is active. If the cooldown has not expired, the request is rejected before the password is validated. Because the failed attempt counter and cooldown timer are globally shared, failed authentication attempts against any endpoint affect all other endpoints. An attacker can exploit this by repeatedly sending invalid authentication requests to any of these endpoints, incrementing the shared counter and waiting for the cooldown period between attempts. By doing so, the attacker can progressively increase the lockout duration until it reaches 24 hours, effectively preventing legitimate users from authenticating. Once the maximum lockout is reached, the attacker can maintain the denial of service indefinitely by waiting for the cooldown to expire and sending another failed attempt, which immediately triggers another 24-hour lockout if no successful login occurred in the meantime. Version 1.8.72 fixes the vulnerability.
Gravité et risque d'exploitation
CVE-2026-33935 obtient un score CVSS de 7.7/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.80 %, ce qui la place devant 55.8 % des CVE référencées.
Que faire ?
- Vérifiez si MyTube (versions < 1.8.72) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://github.com/franklioxygen/MyTube/security/advisories/GHSA-6w95-qgc4-5jxf
- https://github.com/franklioxygen/MyTube/commit/4d89b146b16d08f27d8fd3e0a9122b109335deb1
- https://github.com/franklioxygen/MyTube/commit/752bc7f0ac83df8c881e6b6d5dd6f36bb274ee58
- https://github.com/franklioxygen/MyTube/commit/dd7b4a611fcc5b25a569f379be9a503eb413b6aa
- https://github.com/franklioxygen/MyTube/blob/941035909ee3f96a6f80f38acf70cbc3e66b5098/backend/src/services/loginAttemptService.ts#L13
