CVE-2025-52374: Use of hardcoded cryptographic key in Encryption.cs in hMailServer 5.8.6 and 5.6.9-beta allows attacker to dec

Routine

MEDIUM 4.6DOWNGRADE

CVE-2025-52374 is a medium-severity flaw (CVSS 4.6) affecting hmailserver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Use of hardcoded cryptographic key in Encryption.cs in hMailServer 5.8.6 and 5.6.9-beta allows attacker to decrypt passwords to other servers from hMailAdmin.exe.config file to access other hMailServer admin consoles with configured connections.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	4.6 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 86%)
CISA exploited list	No
Weakness	CWE-321
Published	2025-07-21
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: hmailserver

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-07-21 16:15 UTCPublished CVE record published
2026-06-17 09:36 UTCUpdated Record last modified

hmailserver hmailserver DOWNGRADE

Affected: 5.6.9 beta · 5.8.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.6.9

1. Check installed version

apt-cache policy hmailserver || rpm -q hmailserver || hmailserver --version

2. No fixed release: DOWNGRADE to a release before 5.6.9 (Debian / Ubuntu)

apt-cache madison hmailserver sudo apt install hmailserver=<VERSION_BEFORE_5.6.9> sudo apt-mark hold hmailserver

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list hmailserver sudo dnf downgrade hmailserver-<VERSION_BEFORE_5.6.9> sudo dnf versionlock add hmailserver

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-52374?

hmailserver: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-52374 being exploited?

CVE-2025-52374 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-52374 affect?

CVE-2025-52374 affects hmailserver. Severity is medium (CVSS 4.6). Use of hardcoded cryptographic key in Encryption.cs in hMailServer 5.8.6 and 5.6.9-beta allows attacker to decrypt passwords to other servers from hMailAdmin.exe.config file to access other hMailServer admin consoles with configured connect

How urgent is CVE-2025-52374?

Priority 25/100. Public exploit reference

Related CVEs

CVE-2025-52373 MEDIUM 4.6 DOWNGRADE Use of hardcoded cryptographic key in BlowFish.cpp in hMailServer 5.8.6 and 5.6.9-beta allows attacker to decr
CVE-2025-52372 MEDIUM 5.1 DOWNGRADE An issue in hMailServer v.5.8.6 allows a local attacker to obtain sensitive information via the hmailserver/in

References

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