No advisories yet.
Solution
Upgrade to hMailServer 6.3.6. Until then: keep the REST API off (RestApiPort 0, the default) or open it only to trusted users; keep ProtectStoredSecretsWithDPAPI on (the default); do not grant remote DCOM activation to the hMailServer AppID; and do not give untrusted people an interactive logon on the server.
Workaround
No workaround given by the vendor.
Thu, 08 Oct 2026 15:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Thu, 08 Oct 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Progressive Robot
Progressive Robot hmailserver |
|
| Vendors & Products |
Progressive Robot
Progressive Robot hmailserver |
Thu, 08 Oct 2026 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Heap-based buffer overflow in the legacy Blowfish encryption routine (BlowFishEncryptor::Encode, called by EncryptToString) in Progressive Robot hMailServer 6.0.0 through 6.3.5 allows an authenticated mailbox user to cause a denial of service (service crash), and possibly other unspecified impact. In 6.3.4 and 6.3.5, where the self-service REST API is enabled (it is off by default), the user does this remotely by adding a fetch account whose password is 129 to 247 characters long and not a multiple of 8, and then requesting their personal data export (GET /api/v1/me/export.zip), which encrypts that password with the legacy scheme. The same flaw is reachable on Windows by any local interactive user with no hMailServer credentials, through the COM method Utilities.BlowfishEncrypt, which checked no authentication. It is also reachable by every stored-secret write when ProtectStoredSecretsWithDPAPI is set to 0. For such a length, the routine's padding loop writes up to 7 zero bytes 2 to 232 bytes past the end of its 255-byte heap buffer. The ciphertext it returns is still correct. | |
| Title | Heap-based Buffer Overflow in hMailServer | |
| Weaknesses | CWE-122 | |
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: GitLab
Published:
Updated: 2026-10-08T14:22:03.806Z
Reserved: 2026-09-29T21:04:50.170Z
Link: CVE-2026-103011
Updated: 2026-10-08T14:22:00.524Z
Status : Received
Published: 2026-10-08T11:16:42.270
Modified: 2026-10-08T15:17:31.353
Link: CVE-2026-103011
No data.
OpenCVE Enrichment
Updated: 2026-10-08T13:00:07Z