Heap-based Buffer Overflow in hMailServer
Heap-based buffer overflow in the legacy Blowfish decryption routine (BlowFishEncryptor::DecryptFromString) in Progressive Robot hMailServer 6.0.0 through 6.3.3 on Windows allows a local interactive user with no hMailServer credentials to write bytes of their choosing past the end of a 255-byte heap buffer in the hMailServer service process, which runs as LocalSystem by default. The user does this by passing a long hexadecimal string to the COM method Utilities.BlowfishDecrypt, which checked no authentication. The routine converted hexadecimal input of any length into a fixed 255-byte buffer before decrypting it in place. The result is a denial of service (service crash), and possibly code execution with the privileges of the service account.
CVE-2026-103010
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-103010
hMailServer
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://gitlab.com/hmailserver/hmailserver",
"vendor": "Progressive Robot Ltd",
"product": "hMailServer",
"versions": [
{
"status": "affected",
"version": "6.0.0",
"lessThan": "6.3.4",
"versionType": "semver"
}
],
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-103010
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #12537 · Revision 1
- Added to Heist Feed
- Publisher date