CVE-2025-31161 CrushFTP Authentication Bypass
Attackers can bypass authentication to gain administrative access and compromise the system via a race condition in the AWS4-HMAC authorization method.
- Exploited in the wild
- Since 7 Apr 2025
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-31161?
CVE-2025-31161 is a critical authentication bypass vulnerability in CrushFTP, published on 3 Apr 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
CrushFTP 10 before 10.8.4 and 11 before 11.3.1 allows authentication bypass and takeover of the crushadmin account (unless a DMZ proxy instance is used), as exploited in the wild in March and April 2025, aka "Unauthenticated HTTP(S) port access." A race condition exists in the AWS4-HMAC (compatible with S3) authorization method of the HTTP component of the FTP server. The server first verifies the existence of the user by performing a call to login_user_pass() with no password requirement. This will authenticate the session through the HMAC verification process and up until the server checks for user verification once more. The vulnerability can be further stabilized, eliminating the need for successfully triggering a race condition, by sending a mangled AWS4-HMAC header. By providing only the username and a following slash (/), the server will successfully find a username, which triggers the successful anypass authentication process, but the server will fail to find the expected SignedHeaders entry, resulting in an index-out-of-bounds error that stops the code from reaching the session cleanup. Together, these issues make it trivial to authenticate as any known or guessable user (e.g., crushadmin), and can lead to a full compromise of the system by obtaining an administrative account.
Weakness: CWE-305
Which versions are affected by CVE-2025-31161?
It affects 1 product.
Products include Crushftp Crushftp.
How do I fix CVE-2025-31161?
No fix has been published for CVE-2025-31161 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 28 Apr 2025.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2025-31161 being exploited?
Yes. Attackers have exploited CVE-2025-31161 in the wild since at least 7 Apr 2025, including in ransomware campaigns.
Public exploit code: 1 Exploit-DB entry, 1 Nuclei template and 19 proofs of concept on GitHub.
Other vulnerabilities in CrushFTP
Sources
Also known as CVE-2025-2825, GHSA-c57h-rx24-vf52.