CVE-2026-126614
What it is
The web services listener of Progressive Robot hMailServer 6.3.3 through 6.3.7 does not apply the server's IP ranges to the connections it accepts, which allows a remote unauthenticated attacker to go on guessing account passwords at the listener's sign-ins after the auto-ban has banned the attacker's address. The listener is off by default (WebServicesHttpPort and WebServicesHttpsPort 0). From 6.3.3 its CardDAV, and from 6.3.4 its CalDAV and its Outlook Autodiscover answer to a request that carries credentials, sign an account in with HTTP Basic over HTTPS. A failed sign-in there counts towards the auto-ban as a failed logon on any other protocol does: when the failures counted from one address reach MaxInvalidLogonAttempts (3 within 30 minutes by default), the server writes an IP range that refuses the address for AutoBanMinutes (60 by default), and the SMTP, POP3, IMAP and ManageSieve listeners refuse it. The web services listener asked no IP range when it accepted a connection (in 6.3.3 nothing, from 6.3.4 the country policy alone), so it went on serving such an address, whether its ban had been earned there or on another protocol, and also an address that an administrator's IP range allowing nothing holds. Each failed sign-in there closed only its own connection, and the next connection was accepted, during the ban and after it. The firewall rule and command the auto-ban can drive (AutoBanFirewall and AutoBanCommand, off by default) are told only the SMTP, POP3 and IMAP ports, so that the firewall rule and the packaged hook did not close the listener's ports, and the fail2ban jail packaged for Linux (off by default) lists only the mail and ManageSieve ports. The only limit left on the guesses at one account there was the per-name lockout (AccountLockoutThreshold in hMailServer.ini, 0, off, by default), which has a separate defect fixed in the same release. The flaw is reached on the listener's HTTPS port: behind a TLS-terminating proxy the listener sees the proxy's address for every client, and a ban never named the client there.
At a glance
- Exploitability
- Can be exploited over the network without logging in. Limited direct impact.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: not scored yet.
- Severity: 5.3 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Weakness
- CWE-307
- Record status
- Received
Attack profile CVSS 3.1 · 5.3
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-126614.md and follow it. Check whether this project is affected by CVE-2026-126614. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
