CVE-2026-103010Heap-based Buffer Overflow in hMailServer
Updated under an hour ago ()
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It affects Progressive Robot Ltd hMailServer. Add what you run to find out whether that includes you.
EPSS puts the chance of exploitation in the next 30 days at 0.16%, higher than 5% of scored CVEs.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-122
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- 0.16% (percentile 5)
- Assigned by
- GitLab
- NVD analysis
- Deferred
- Record last updated
- Oct 8, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Progressive Robot Ltd hMailServer progressive_robot:hmailserver (from the name) | from 6.0.0 before 6.3.4 | CNA record |
References
- https://gitlab.com/hmailserver/hmailserver/-/commit/135a1908ff820ed587d5f180f98c53bd010d8931
- https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.4
- https://gitlab.com/hmailserver/hmailserver/-/work_items/49
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.