Vulnerability · Published Oct 28, 2026 · Assigned by VulnCheck
CVE-2026-118691xianyu-auto-reply-fix through 2.0.7 Unauthenticated Message Sending via /send-message
Low 3.7
In plain English
A low-severity security flaw in xianyu-auto-reply-fix from GuDong2003. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities).
Official description
xianyu-auto-reply-fix through 2.0.7 contains a missing authorization vulnerability in the POST /send-message endpoint that allows unauthenticated attackers to send messages from other users' accounts using publicly known default API secrets. Attackers can supply the hard-coded api_key and another user's cookie_id, plus chosen chat_id, to_user_id and message values, to send arbitrary Xianyu messages to buyers from that merchant account.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| GuDong2003 | xianyu-auto-reply-fix | 0 – through 2.0.7 |
Weakness: CWE-1188 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- GitHub Issue #116 issue-tracking
- https://github.com/GuDong2003/xianyu-auto-reply-fix product
- https://github.com/GuDong2003/xianyu-auto-reply-fix/blob/v2.0.7/reply_server.py#L2347-L2475 technical-description
- https://github.com/GuDong2003/xianyu-auto-reply-fix/blob/v2.0.7/db_manager.py#L1011 technical-description
- https://github.com/GuDong2003/xianyu-auto-reply-fix/commit/999cfe61c401322d9893eb81ad1a76beabba6cfb patch
- VulnCheck Advisory: xianyu-auto-reply-fix through 2.0.7 Unauthenticated Message Sending via /send-message third-party-advisory
- https://hackmd.io/@hieuPenguinnn/xianyu-auto-reply-default-secret-cross-user-message-send exploit