CVE-2026-107587: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-j6xf-vpp5-5357
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CVSS 5.9
CWE-295
Published
Advisory Summary

CVE-2026-107587 is a MODERATE (CVSS 5.9) security vulnerability vulnerability (CWE-295: Improper Certificate Validation) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not validate, or incorrectly validates, a certificate.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-107587 at a Glance

CVE Identifier CVE-2026-107587
GHSA Identifier GHSA-j6xf-vpp5-5357
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-295: Improper Certificate Validation
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-107587

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-107587, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-295: Improper Certificate Validation, where the product does not validate, or incorrectly validates, a certificate. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Improper certificate validation in the webmail of Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to have S/MIME-encrypted mail that the account later sends to another correspondent also encrypted to the attacker's key. When its recipient opened a signed message, the webmail kept the signer's certificate for encrypting replies whether or not the server found its chain trusted, under the first e-mail address the certificate listed rather than the message's From address, and beside any certificate already held for that address. Encrypted mail later sent from the webmail to that address was encrypted to every certificate held for it, so a holder of the kept certificate's key who obtains a copy of such a message can read it.

References

NVD — CVE-2026-107587 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-107587
gitlab.com/hmailserver/hmailse... WEB
https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6
gitlab.com/hmailserver/hmailse... WEB
https://gitlab.com/hmailserver/hmailserver/-/work_items/66

Frequently Asked Questions

What is CVE-2026-107587?
CVE-2026-107587 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-295: Improper Certificate Validation.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-107587?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-107587?
CVE-2026-107587 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N.
What CWE is associated with CVE-2026-107587?
CVE-2026-107587 is classified under CWE-295: Improper Certificate Validation (The product does not validate, or incorrectly validates, a certificate.).
How can I check Maven dependencies for CVE-2026-107587?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-j6xf-vpp5-5357",
  "modified" : "2026-10-08T12:34:27Z",
  "published" : "2026-10-08T12:34:27Z",
  "aliases" : [ "CVE-2026-107587" ],
  "details" : "Improper certificate validation in the webmail of Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to have S/MIME-encrypted mail that the account later sends to another correspondent also encrypted to the attacker's key. When its recipient opened a signed message, the webmail kept the signer's certificate for encrypting replies whether or not the server found its chain trusted, under the first e-mail address the certificate listed rather than the message's From address, and beside any certificate already held for that address. Encrypted mail later sent from the webmail to that address was encrypted to every certificate held for it, so a holder of the kept certificate's key who obtains a copy of such a message can read it.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-107587"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"
  }, {
    "type" : "WEB",
    "url" : "https://gitlab.com/hmailserver/hmailserver/-/work_items/66"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-295" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-08T12:17:16Z"
  }
}