CVE-2025-31161CrushFTP 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 2…
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CISA lists it as known exploited since Apr 7, 2025; federal agencies had to remediate by Apr 28, 2025, and it is known to be used in ransomware. Treat that date as your deadline.
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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.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-305
- Known exploited
- Added to CISA KEV Apr 7, 2025; federal remediation due Apr 28, 2025; known ransomware useApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- EPSS (exploitation in the next 30 days)
- 99.97% (percentile 100)
- Assigned by
- mitre
- NVD analysis
- Analyzed
- Record last updated
- Oct 21, 2025
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
CrushFTP CrushFTP crushftp:crushftp (from the name) | from 10 before 10.8.4; from 11 before 11.3.1 | CNA record |
crushftp crushftp crushftp:crushftp | from 10.0.0 before 10.8.4; from 11.0.0 before 11.3.1 | NVD |
References
- https://outpost24.com/blog/crushftp-auth-bypass-vulnerability/third-party-advisory
- https://crushftp.com/crush11wiki/Wiki.jsp?page=Update#section-Update-VulnerabilityInfovendor-advisory
- https://attackerkb.com/topics/k0EgiL9Psz/cve-2025-2825/rapid7-analysisexploit, third-party-advisory
- https://projectdiscovery.io/blog/crushftp-authentication-bypassexploit, third-party-advisory
- https://www.darkreading.com/vulnerabilities-threats/disclosure-drama-clouds-crushftp-vulnerability-exploitationpress/media-coverage
- https://www.huntress.com/blog/crushftp-cve-2025-31161-auth-bypass-and-post-exploitationexploit, third-party-advisory
- https://www.infosecurity-magazine.com/news/crushftp-flaw-exploited-disclosure/press/media-coverage
- https://www.vicarius.io/vsociety/posts/cve-2025-31161-detect-crushftp-vulnerabilityexploit, third-party-advisory
- https://www.vicarius.io/vsociety/posts/cve-2025-31161-mitigate-crushftp-vulnerabilitymitigation, third-party-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-31161us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.