Libraesva Email Security Gateway

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

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 29 Sep 2025, 10 days after the CVE record was published.

How likely is exploitation in the next 30 days?

1.9%

EPSS score, percentile 79.2 of all scored records

How severe?

6.1 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

Required action (CISA), due 20 Oct 2025: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected: 4.5 up to, not including, 5.0.31; 5.1 up to, not including, 5.1.20; 5.2 up to, not including, 5.2.31; 5.3 up to, not including, 5.4.8; 5.5 up to, not including, 5.5.7

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CISA due date for this action: 20 October 2025.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Libraesva Email Security Gateway
Status	Versions
Affected	4.5 up to, not including, 5.0.31
Affected	5.1 up to, not including, 5.1.20
Affected	5.2 up to, not including, 5.2.31
Affected	5.3 up to, not including, 5.4.8
Affected	5.5 up to, not including, 5.5.7

Versions not listed are: unaffected.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Libraesva Email Security Gateway (ESG) contains a command injection vulnerability which allows command injection via a compressed e-mail attachment.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

CISA added CVE-2025-59689 to its Known Exploited Vulnerabilities (KEV) catalog on 29 Sep 2025.
CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
The due date CISA sets for the required action is 20 Oct 2025.
The CVE record was published on 19 Sep 2025, 10 days before it was added to KEV.
The CVE record carries a CVSS v3.1 base score of 6.1 (Medium), given by its CNA.
FIRST's EPSS model puts the probability of exploitation in the next 30 days at 1.9% (percentile 79.2), as of 28 Oct 2026.
CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

Date	Event
19 Sep 2025	CVE record published
29 Sep 2025	Added to CISA KEV
20 Oct 2025	CISA due date for the required action
26 Feb 2026	CVE record last updated