Callback WidgetApplication · Phpjabbers

CVE-2023-40756

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 Callback Widget v1.0. 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 · moderate confidence

User enumeration vulnerability in PHPJabbers Callback Widget v1.0 password recovery function. The application returns different error messages or responses for valid versus invalid usernames/emails during password recovery, allowing attackers to identify valid user accounts through systematic probing.

MitigationModify password recovery to return identical responses (e.g., 'If an account exists with this email, a recovery link has been sent') regardless of whether the submitted email/username exists in the system.

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
Callback WidgetApplication
Affected:= 1.0

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 PHPJabbers Callback Widget installation
    Locate the web application files and check for callback-widget directory or similar PHPJabbers installation paths. Check version.php or configuration files for version number.
    Affected if The installed version is PHPJabbers Callback Widget version 1.0
  2. Verify password recovery functionality exists
    Navigate to the password recovery or forgot password page in the web interface. Look for forms accepting email or username input related to password reset.
    Affected if The password recovery form is accessible and accepts user input
  3. Test response for non-existent email
    Submit a fake or non-existent email address (e.g., [email protected]) to the password recovery form and capture the HTTP response or error message displayed.
    Affected if The application returns a specific error message indicating the email does not exist
  4. Test response for existing email
    Submit a known-valid email address (e.g., admin@localhost or a test account created during installation) to the password recovery form and capture the response.
    Affected if The application returns a different response (e.g., confirmation that email was sent) compared to the non-existent email test, confirming user enumeration is possible

A user is affected if PHPJabbers Callback Widget v1.0 is installed and the password recovery function returns distinguishable responses for valid versus invalid email addresses.

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

Modify password recovery to return identical responses (e.g., 'If an account exists with this email, a recovery link has been sent') regardless of whether the submitted email/username exists in the system.

Fix this in Callback Widget 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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Scan for this in your stack

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dbcve dependency scanner

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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-2023-40756 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