CVE-2026-104659
Missing Host header validation and missing throttling of failed administrator sign-ins in the REST…
- Risk score
- 51/100
- CVSS
- 7.5 v3.1
- Exploit chance (30 days)
- 0.1%
- Published
- 8 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it is
- Missing Host header validation and missing throttling of failed administrator sign-ins in the REST API listener of Progressive Robot hMailServer 6.0.0 through 6.3.5 allow a remote attacker to brute-force the server administrator's password through the administrator's own browser by DNS rebinding. The listener, which i…
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 7.5 high
- Remotely exploitable without logging in
References
Original description
Missing Host header validation and missing throttling of failed administrator sign-ins in the REST API listener of Progressive Robot hMailServer 6.0.0 through 6.3.5 allow a remote attacker to brute-force the server administrator's password through the administrator's own browser by DNS rebinding. The listener, which is off by default and bound to the loopback when enabled, answered requests whatever their Host header named, and a failed sign-in with the administrator's password from the loopback was neither auto-banned nor delayed. A web page whose host name the attacker rebinds to 127.0.0.1, opened in a browser on the server, can therefore send authenticated requests to the listener, read the answers and try administrator passwords at full speed until one is accepted, giving the attacker full administrative control of the mail server.
Last activity 8 Oct 2026. Patch Forecast updates every hour.