CVE-2025-59689 Libraesva Email Security Gateway Command Injection Vulnerability
Libraesva Email Security Gateway (ESG) contains a command injection vulnerability which allows command injection via a compressed e-mail attachment.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 29 Sep 2025.
- Rated Medium severity (CVSS 6.1, scored by Vendor).
- This product type is often exposed to the internet, which is where attackers scan for it first.
- It has been in the catalogue for 403 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
Libraesva ESG 4.5 through 5.5.x before 5.5.7 allows command injection via a compressed e-mail attachment. For ESG 5.0 a fix has been released in 5.0.31. For ESG 5.1 a fix has been released in 5.1.20. For ESG 5.2 a fix has been released in 5.2.31. For ESG 5.4 a fix has been released in 5.4.8. For ESG 5.5. a fix has been released in 5.5.7.
Affected Versions
| Product | Versions |
|---|---|
| Libraesva Email Security Gateway | 4.5 to before 5.0.31 5.1 to before 5.1.20 5.2 to before 5.2.31 5.3 to before 5.4.8 5.5 to before 5.5.7 |
From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Libraesva Email Security Gateway. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
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