Virtual Event: Threat Detection and Incident Response Summit - Watch Sessions
Connect with us

Hi, what are you looking for?


Malware & Threats

Hacker Releases Exploit for vBulletin Zero-Day Vulnerability

A hacker has released an exploit for an unpatched remote command execution vulnerability affecting the vBulletin forum software.

A hacker has released an exploit for an unpatched remote command execution vulnerability affecting the vBulletin forum software.

A proof-of-concept (PoC) exploit for the zero-day was published on the Full Disclosure mailing list by an individual who wanted to remain anonymous. It’s unclear why they have decided to release the information before vBulletin developers could create a patch.

The vulnerability, to which MITRE assigned the CVE identifier CVE-2019-16759, is said to affect vBulletin 5.x through 5.5.4 (the latest version), and it allows an unauthenticated attacker to execute arbitrary commands by sending a specially crafted HTTP POST request to the targeted vBulletin website.

Researchers at cybersecurity firm Tenable have analyzed the PoC exploit and have confirmed that it works on default vBulletin configurations.

“These commands would be executed with the permissions of the user account that the vBulletin service is utilizing. Depending on the service user’s permissions, this could allow complete control of a host,” Tenable said.

Others also confirmed that the exploit works.

There are roughly 20,000 websites currently powered by vBulletin, including some owned by important organizations. However, a majority use versions 3 and 4, and only around 1,100 use version 5, which is affected by this flaw. On the other hand, a researcher says he has tested many vBulletin 5.x installations and only some of them appear to be vulnerable to attacks.

Advertisement. Scroll to continue reading.

Organizers of the DEF CON hacking conference have temporarily shut down the official DEF CON forum to test the impact of the vBulletin vulnerability and implement mitigations.

SecurityWeek has reached out to vBulletin developers for comment and information on the availability of a patch, but they have yet to respond.

Exploit acquisition firm Zerodium is currently offering up to $10,000 for remote code execution exploits targeting vBulletin, but this particular exploit might not be worth the top reward if it impacts a relatively small number of websites.

UPDATE. According to some reports, the vulnerability has already been exploited in the wild.

Related: vBulletin Patches Disclosed Vulnerabilities

Related: vBulletin Resets Passwords After Server Hack

Related: Attackers Exploit vBulletin Flaw to Hack Servers

Written By

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

SecurityWeek’s Threat Detection and Incident Response Summit brings together security practitioners from around the world to share war stories on breaches, APT attacks and threat intelligence.


Securityweek’s CISO Forum will address issues and challenges that are top of mind for today’s security leaders and what the future looks like as chief defenders of the enterprise.


Expert Insights

Related Content


Less than a week after announcing that it would suspended service indefinitely due to a conflict with an (at the time) unnamed security researcher...

Data Breaches

OpenAI has confirmed a ChatGPT data breach on the same day a security firm reported seeing the use of a component affected by an...


The changing nature of what we still generally call ransomware will continue through 2023, driven by three primary conditions.


A recently disclosed vBulletin vulnerability, which had a zero-day status for roughly two days last week, was exploited in a hacker attack targeting the...

Risk Management

The supply chain threat is directly linked to attack surface management, but the supply chain must be known and understood before it can be...


The latest Chrome update brings patches for eight vulnerabilities, including seven reported by external researchers.


Patch Tuesday: Microsoft warns vulnerability (CVE-2023-23397) could lead to exploitation before an email is viewed in the Preview Pane.


Apple has released updates for macOS, iOS and Safari and they all include a WebKit patch for a zero-day vulnerability tracked as CVE-2023-23529.