Cyber Posture

CVE-2026-33890

CriticalPublic PoC

Published: 27 March 2026

Published
27 March 2026
Modified
01 April 2026
KEV Added
Patch
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0039 60.2th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

MyTube is a self-hosted downloader and player for several video websites Prior to version 1.8.71, an unauthenticated attacker can register an arbitrary passkey and subsequently authenticate with it to obtain a full admin session. The application exposes passkey registration endpoints…

more

without requiring prior authentication. Any successfully authenticated passkey is automatically granted an administrator token, allowing full administrative access to the application. This enables a complete compromise of the application without requiring any existing credentials. Version 1.8.71 fixes the issue.

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly addresses permitting passkey registration without identification or authentication by requiring explicit authorization and documentation of such actions.

prevent

Requires identity verification prior to issuing authenticators like passkeys, preventing unauthenticated self-registration of arbitrary credentials.

prevent

Enforces approved access authorizations on endpoints to block unauthenticated access to passkey registration and subsequent admin token issuance.

Security SummaryAI

CVE-2026-33890 affects MyTube, a self-hosted downloader and player for several video websites, in versions prior to 1.8.71. The vulnerability stems from exposed passkey registration endpoints that do not require prior authentication, allowing an unauthenticated attacker to register an arbitrary passkey. Upon successful authentication with this passkey, the application automatically grants a full administrator token, enabling complete administrative access without needing any existing credentials. This issue is classified under CWE-284 (Improper Access Control) with a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

An unauthenticated remote attacker can exploit this vulnerability over the network with low complexity and no user interaction. By simply accessing the public passkey registration endpoint, the attacker creates a custom passkey, authenticates with it, and obtains an admin session token. This grants full control over the MyTube instance, including potential data exfiltration, modification of application settings, or execution of arbitrary actions, leading to a total compromise of the affected system.

The GitHub security advisory (GHSA-378w-xh68-qrc8) and the fixing commit (d6c1275a7ff7ffd3d51b53c333237f4d572580ac) confirm that upgrading to MyTube version 1.8.71 resolves the issue by addressing the unauthenticated passkey registration and automatic admin token granting. Security practitioners should immediately patch affected instances and review access logs for unauthorized admin sessions.

Details

CWE(s)

Affected Products

franklioxygen
mytube
≤ 1.8.71

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

The vulnerability allows unauthenticated remote exploitation of a public-facing web application (MyTube) to register a passkey and obtain full administrator access, directly mapping to T1190: Exploit Public-Facing Application.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

References