CVE-2025-59689 — Libraesva Email Security Gateway Command Injection Vulnerability

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 releas

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
Libraesva	Email Security Gateway	4.5, 5.1, 5.2, 5.3, 5.5

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2025-09-29. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2025-09-19T00:00:00.000Z
• Last modified: 2026-02-26T17:48:25.122Z
• Added to CISA KEV: 2025-09-29
• BOD 22-01 due: 2025-10-20

09References

• www.libraesva.com — https://www.libraesva.com/security-blog/
• docs.libraesva.com — https://docs.libraesva.com/knowledgebase/security-advisory-command-injection-vul…