CVE-2025-52373: Use of hardcoded cryptographic key in BlowFish.cpp in hMailServer 5.8.6 and 5.6.9-beta allows attacker to decr

Routine

MEDIUM 4.6DOWNGRADE

CVE-2025-52373 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 BlowFish.cpp in hMailServer 5.8.6 and 5.6.9-beta allows attacker to decrypt passwords used in database connections from hMailServer.ini config file.

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	0.4% (top 71%)
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-2025-52373?

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

Is CVE-2025-52373 being exploited?

CVE-2025-52373 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-2025-52373 affect?

CVE-2025-52373 affects hmailserver. Severity is medium (CVSS 4.6). Use of hardcoded cryptographic key in BlowFish.cpp in hMailServer 5.8.6 and 5.6.9-beta allows attacker to decrypt passwords used in database connections from hMailServer.ini config file.

How urgent is CVE-2025-52373?

Priority 28/100. Public exploit reference

Related CVEs

CVE-2025-52374 MEDIUM 4.6 DOWNGRADE Use of hardcoded cryptographic key in Encryption.cs in hMailServer 5.8.6 and 5.6.9-beta allows attacker to dec
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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