A zero-day vulnerability in the software of the American company Citrix can still pose a risk to almost a hundred Belgian companies.

The American software company reported a zero-day vulnerability that still poses a threat to 97 Belgian companies. This number comes from Shadowserver, a non-profit organization focused on cybersecurity that works with a number of governments.

The problem

The zero-day vulnerability carries the code CVE-2023-3519 and scores a 9.8 on the CVSS scale, making it a potentially serious problem. Affected products include Citrix ADC and Citrix Gateway, now renamed to NetScaler ADC and NetScaler Gateway. This vulnerability could allow attackers to remotely execute malicious code. We’ve already reported about it, but Shadowserver’s stats weren’t known at the time.

At least one American organization is now affected, reports the Cybersecurity and Infrastructure Security Agency. However, according to Shadowserver, the problem is global and includes 97 individual Belgian servers that are compromised. The organization shared the information about what was then called Twitter.

In addition to CVE-2023-3519, Citrix also reported two other vulnerabilities, but has since published information on the vulnerable IP addresses in all three cases. Shadowserver didn’t share numbers on the other two. There was also a vulnerability at Citrix last year, which was then actively exploited by Chinese hackers.

This article was originally published on July 25, 2023. Text has been updated with the latest information.