Exploited. On CISA's list since 2023-05-26.
Barracuda Networks ESG Appliance Improper Input Validation Vulnerability
CVE-2023-2868 · Barracuda Networks Email Security Gateway (ESG) Appliance · Published 2023-05-24
How bad would it be?
9.8 out of 10
CVSS rates it critical: about as damaging as flaws get.
How likely is it to be used?
87%
Estimated chance of exploitation in the next 30 days, among the top 1% of all scored flaws (EPSS, 2026-10-29).
Is it already being used?
Yes
CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 1232 days ago (2023-06-16).
What CISA says to do
Apply updates per vendor instructions.
Barracuda Email Security Gateway (ESG) appliance contains an improper input validation vulnerability of a user-supplied .tar file, leading to remote command injection.
What the flaw is
A remote command injection vulnerability exists in the Barracuda Email Security Gateway (appliance form factor only) product effecting versions 5.1.3.001-9.2.0.006. The vulnerability arises out of a failure to comprehensively sanitize the processing of .tar file (tape archives). The vulnerability stems from incomplete input validation of a user-supplied .tar file as it pertains to the names of the files contained within the archive. As a consequence, a remote attacker can specifically format these file names in a particular manner that will result in remotely executing a system command through Perl's qx operator with the privileges of the Email Security Gateway product. This issue was fixed as part of BNSF-36456 patch. This patch was automatically applied to all customer appliances.
From the NVD.
Fixes and advisories
Learn this
Explore this week’s weaknesses and all learning topics
Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.
CWE-20 · CISA KEV; NVD record: cve-coordination@google.com. We have not selected a close learning match for this label.
CWE-77 · NVD record: nvd@nist.gov. We have not selected a close learning match for this label.
CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.
On SentryFeed
No story in the last 14 days has mentioned it.
Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.