CVE-2023-40765Public exploitNetwork attack vector

Account enumeration via password-recovery response discrepancies

Published Aug 28, 2023 · Updated Oct 2, 2024

User enumeration in PHPJabbers Event Booking Calendar 4.0 allows remote attackers to identify valid accounts through password recovery. The password-recovery workflow returns different messages for registered and unregistered user identifiers, exposing an account-existence oracle. No authentication or user interaction is required; the disclosed identifiers can focus later password brute-force attempts, but the flaw does not itself grant account access.

CVSS severity9.8
Critical
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

User enumeration in PHPJabbers Event Booking Calendar 4.0 allows remote attackers to identify valid accounts through password recovery. The password-recovery workflow returns different messages for registered and unregistered user identifiers, exposing an account-existence oracle. No authentication or user interaction is required; the disclosed identifiers can focus later password brute-force attempts, but the flaw does not itself grant account access.

The record

CVE
CVE-2023-40765
Published
Aug 28, 2023
Updated
Oct 2, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-209, T1589.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-209Generation of Error Message Containing Sensitive Information
T1589.001Gather Victim Identity Information: Credentials

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo