CVE-2026-23848: MyTube Rate Limiting Bypass Vulnerability

CVE-2026-23848 Overview

CVE-2026-23848 is a rate limiting bypass vulnerability affecting MyTube, a self-hosted downloader and player for several video websites. Prior to version 1.7.71, unauthenticated attackers can bypass IP-based rate limiting on general API endpoints by spoofing client IPs through manipulation of the X-Forwarded-For header. This enables unlimited requests to protected endpoints, potentially leading to denial of service (DoS) attacks and abuse of other rate-limited functionality.

Critical Impact

Attackers can bypass rate limiting protections to flood API endpoints with unlimited requests, enabling denial of service attacks and circumventing security controls designed to prevent abuse of the application.

Affected Products

• MyTube versions prior to 1.7.71

Discovery Timeline

• 2026-01-19 - CVE-2026-23848 published to NVD
• 2026-01-19 - Last updated in NVD database

Technical Details for CVE-2026-23848

Vulnerability Analysis

This vulnerability is classified under CWE-807 (Reliance on Untrusted Inputs in a Security Decision). The core issue stems from the application's trust of the X-Forwarded-For HTTP header for client IP identification without proper validation. When a reverse proxy or load balancer is in use, applications often rely on this header to determine the original client IP address. However, since HTTP headers can be arbitrarily set by clients, trusting this value for security-critical decisions like rate limiting creates an exploitable weakness.

The attack allows an unauthenticated attacker to submit requests with fabricated IP addresses in the X-Forwarded-For header, causing the rate limiting mechanism to track each spoofed IP separately. This effectively grants the attacker unlimited request capacity, as each forged IP receives its own rate limit allocation.

Root Cause

The root cause is improper IP extraction logic that blindly trusts the X-Forwarded-For header value provided by clients. The application failed to implement proper validation or use a trusted proxy configuration to ensure the header value originated from a legitimate proxy rather than being directly manipulated by an attacker.

Attack Vector

The vulnerability is exploitable over the network without authentication. An attacker simply needs to include a spoofed X-Forwarded-For header in their HTTP requests to the MyTube API. By rotating through arbitrary IP addresses in this header with each request, the attacker can bypass any IP-based rate limits and send unlimited requests to protected endpoints.

The security patch introduces a new getClientIp utility function for improved IP extraction and validation:

 import * as storageService from "./services/storageService";
 import { logger } from "./utils/logger";
 import {
+  getClientIp,
   validateCloudThumbnailCachePath,
   validateRedirectUrl,
 } from "./utils/security";

Source: GitHub Commit Update

Detection Methods for CVE-2026-23848

Indicators of Compromise

• High volume of requests from a single actual source IP but with varying X-Forwarded-For header values
• Unusual patterns of API requests that exceed normal usage but don't trigger rate limiting
• Log entries showing rapidly changing client IP addresses from consistent network infrastructure

Detection Strategies

• Implement log correlation to identify requests where the actual connecting IP differs significantly from the X-Forwarded-For header
• Monitor for abnormal request volumes to rate-limited endpoints that don't trigger existing protections
• Deploy web application firewall rules to detect header manipulation patterns

Monitoring Recommendations

• Review API access logs for suspicious patterns of X-Forwarded-For header values
• Set up alerts for sudden spikes in API traffic that may indicate rate limit bypass attempts
• Monitor server resource utilization for unexpected increases that could indicate DoS activity

How to Mitigate CVE-2026-23848

Immediate Actions Required

• Upgrade MyTube to version 1.7.71 or later immediately
• Review and restrict which proxies are trusted to set the X-Forwarded-For header
• Consider implementing additional rate limiting at the infrastructure level (e.g., reverse proxy, CDN, or WAF)

Patch Information

The vulnerability has been patched in MyTube version 1.7.71. The fix introduces a new getClientIp utility function in the security module that implements proper IP extraction and validation. Users should update to this version or later to remediate the vulnerability.

For more information, see the GitHub Security Advisory and the patch commit.

Workarounds

• Configure your reverse proxy to overwrite (not append to) the X-Forwarded-For header with the actual connecting client IP
• Implement additional rate limiting at the network or infrastructure level that does not rely on HTTP headers
• Consider temporarily restricting access to rate-limited API endpoints until the patch can be applied

# Example nginx configuration to set trusted proxy handling
# Add to your nginx server block before proxying to MyTube
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $remote_addr;
# This overwrites any client-provided X-Forwarded-For header