Unverified Ownership in hMailServer
- Exploited
- No known exploitation
- Fix
- Fixed in 6.3.8
- Who is exposed
- Specific setups only
Do first: Upgrade to a fixed version: 6.3.8.
- Published
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 12/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
A local user with a low-privilege account can run code as the hMailServer service account or as an administrator when the Windows installer sets up or upgrades hMailServer in a program folder that other accounts could write to, such as one created at the root of a drive. The attack requires an administrator to run that setup or upgrade, and the default installation under Program Files is not affected.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
Unverified ownership in the Windows installer of Progressive Robot hMailServer 6.3.7 allows a local authenticated user to run code as the mail server's service account or as an administrator when setup installs into, or upgrades, a program folder that accounts other than the administrators could write before, such as one made beforehand at the root of a drive. 6.3.7 fixed CVE-2026-107571 by giving the program folder, Bin and ControlPanel permissions that only administrators may change, but setup refused nothing that was already in them, or in the folders that hold the event script, the add-ons and the database scripts: a program, a library, a script or a settings file that another account owns, or whose own permissions let another account change it, is kept with that owner and those permissions, which the hardening of the folders does not take away. Setup then runs programs from Bin with the administrator's elevated rights, and the service, which runs as LocalSystem or as its virtual account, runs them and the event script, so that a library such an account placed in Bin is loaded in place of the system's; the account can still change the file after the installation. The default installation under Program Files is not affected.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure5/25Specific setups only
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.3/10CVSS 7.3
- No patch0/5No signal
What would change the score
- Would score about 62 if added to CISA KEV
- Would score about 57 if CISA's SSVC rates exploitation active
- Would score about 22 if CISA's SSVC rates it automatable
What to do
Upgrade to a fixed version: 6.3.8.
Workaround: Install hMailServer under Program Files, or into a new folder inside one that only administrators may change.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126624 (Unverified Ownership in hMailServer), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-126624 (entry last updated 2026-11-11): Affected: - Progressive Robot Ltd hMailServer: versions 6.3.7 Fixed versions: 6.3.8. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. Attacker needs: local access, low-privilege login, a user action. Workaround: Install hMailServer under Program Files, or into a new folder inside one that only administrators may change. (source: https://www.cve.org/CVERecord?id=CVE-2026-126624) CISA KEV: CVE-2026-126624 is not listed as of cve.now's last read. This KEV status is for CVE-2026-126624 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://gitlab.com/hmailserver/hmailserver/-/work_items/78 - https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.8 - https://www.cve.org/CVERecord?id=CVE-2026-107571 - https://www.cve.org/CVERecord?id=CVE-2026-126624 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-126624 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126624.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- Progressive Robot Ltd hMailServer
6.3.7
Evidence 5
CVE record · 3
Establishes: The identifier and description.
- Record
- Record
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-126624
Is CVE-2026-126624 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-126624?
hMailServer: version 6.3.7.Source: cve.now feed data
How do I fix CVE-2026-126624?
Upgrade hMailServer to version 6.3.8, which the vendor's fix quote names as the fixed release. If you cannot upgrade yet, the listed workaround is to install hMailServer under Program Files, or into a new folder inside one that only administrators may change.Source: cve.org