Event Booking CalendarApplication · Phpjabbers

CVE-2023-40765

CRITICAL · 9.8 CVSS v3.1 Published 2023-08-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
User enumeration is found in PHPJabbers Event Booking Calendar v4.0. This issue occurs during password recovery, where a difference in messages could allow an attacker to determine if the user is valid or not, enabling a brute force attack with valid users.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

User enumeration vulnerability in PHPJabbers Event Booking Calendar v4.0 password recovery function. The application reveals different error messages for existing versus non-existing user accounts during password reset, allowing attackers to harvest valid usernames and conduct targeted brute force attacks.

MitigationImplement uniform error messaging for password recovery regardless of user existence status. Return the same response (e.g., 'If an account exists with this email, a reset link has been sent') for both valid and invalid inputs.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Event Booking CalendarApplication
Affected:= 4.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed version
    Check the software version in the application admin panel under 'Help' or 'About', or inspect the source code files for a version marker
    Affected if The installed version is exactly 4.0 (note: only version 4.0 is listed as affected)
  2. Locate the password recovery endpoint
    Find the 'Forgot Password' or password reset form in the login page of the application
    Affected if The password recovery function exists and is accessible
  3. Test with a non-existing account
    Submit an email address or username that does not exist in the system to the password recovery form and note the exact error message or response
    Affected if The application returns a specific error message indicating the account does not exist
  4. Test with an existing account
    Submit a valid email address or username that is registered in the system to the password recovery form and note the exact error message or response
    Affected if The application returns a different message than the non-existing account test, such as confirming the account was found or sending a reset email
  5. Compare the responses
    Review both error messages side by side to determine if they differ based on user existence
    Affected if Different messages are returned for existing versus non-existing accounts (user enumeration is present)

If the password recovery function returns distinct error messages for valid versus invalid accounts, the environment is affected by this user enumeration vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement uniform error messaging for password recovery regardless of user existence status. Return the same response (e.g., 'If an account exists with this email, a reset link has been sent') for both valid and invalid inputs.

Fix this in Event Booking Calendar Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-40765 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data