GHSA-J6XF-VPP5-5357
Vulnerability from github – Published: 2026-10-08 12:34 – Updated: 2026-10-08 12:34Improper 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.
{
"affected": [],
"aliases": [
"CVE-2026-107587"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-08T12:17:16Z",
"severity": "MODERATE"
},
"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\u0027s key. When its recipient opened a signed message, the webmail kept the signer\u0027s 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\u0027s 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\u0027s key who obtains a copy of such a message can read it.",
"id": "GHSA-j6xf-vpp5-5357",
"modified": "2026-10-08T12:34:27Z",
"published": "2026-10-08T12:34:27Z",
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.