CVE-2023-40764: User enumeration is found in PHP Jabbers Car Rental Script v3.0

This month

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2023-40764 is a critical-severity flaw (CVSS 9.8) affecting car rental script. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

User enumeration is found in PHP Jabbers Car Rental Script v3.0. 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.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-209
Published	2023-08-28
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: phpjabbers

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-08-28 13:15 UTCPublished CVE record published
2026-06-17 06:19 UTCUpdated Record last modified

phpjabbers car rental script DOWNGRADE

Affected: 3.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0

1. Check installed version

apt-cache policy car-rental-script || rpm -q car-rental-script || car-rental-script --version

2. No fixed release: DOWNGRADE to a release before 3.0 (Debian / Ubuntu)

apt-cache madison car-rental-script sudo apt install car-rental-script=<VERSION_BEFORE_3.0> sudo apt-mark hold car-rental-script

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list car-rental-script sudo dnf downgrade car-rental-script-<VERSION_BEFORE_3.0> sudo dnf versionlock add car-rental-script

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-40764?

car rental script: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-40764 being exploited?

CVE-2023-40764 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-40764 affect?

CVE-2023-40764 affects car rental script. Severity is critical (CVSS 9.8). User enumeration is found in PHP Jabbers Car Rental Script v3.0. 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

How urgent is CVE-2023-40764?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2023-48837 MEDIUM 5.4 DOWNGRADE Car Rental Script 3.0 is vulnerable to Multiple HTML Injection issues via SMS API Key or Default Country Code.
CVE-2023-48836 MEDIUM 5.4 DOWNGRADE Car Rental Script 3.0 is vulnerable to Multiple Stored Cross-Site Scripting (XSS) issues via the name, plugin_
CVE-2023-48835 HIGH 8.8 DOWNGRADE Car Rental Script v3.0 is vulnerable to CSV Injection via a Language > Labels > Export action.
CVE-2023-48834 HIGH 7.5 DOWNGRADE A lack of rate limiting in pjActionAjaxSend in Car Rental v3.0 allows attackers to cause resource exhaustion.
CVE-2023-40754 HIGH 8.8 DOWNGRADE In PHPJabbers Car Rental Script 3.0, lack of verification when changing an email address and/or password (on t

References

← Back to latest CVEs