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Vulnerabilities

Vulnerability · CVE-2026-107568

Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows…

Published Oct 19, 2026 · catalog updated Oct 20, 2026 · the affected product

Open the advisory

Exploitation likelihood is not on this record for CVE-2026-107568. A missing EPSS score is not a low risk. Compare the affected product with the linked advisory before you change production.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Not established
Affected products
See sources for product scope

Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows an authenticated user to send mail through the server as any address. A Sieve notify sends a notification message, and its :from tag names the sender; the server set the notification's From header to that :from as the script wrote it, without checking that the address belongs to the account - the check that the Sieve vacation action applies to its own :from, and that the server applies to the sender of mail queued over COM or sent from the webmail. An account that can store a Sieve script (over ManageSieve, the REST API's self-service filter, or the administration interface) could therefore have the server send a notification from any address, on this server or anywhere; and where the claimed address is at a domain the server hosts with DKIM signing enabled, the server signed the notification with that domain's DKIM key, because it signs by the From header's domain, producing forged mail aligned to pass the domain's DMARC policy. The notify action and this behaviour were introduced in 6.2.22. In the mail-rule engine, a rule's Reply was likewise sent from whatever address the action named, whoever the rule belonged to, so that an account acting on its own rules over COM, a domain administrator, or an API key confined to a domain (over the REST API from 6.3.4) could have a domain's or an account's rule reply from any address, signed, where that address is at a domain the server hosts with DKIM signing enabled, with that domain's key.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-107568

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for CVE-2026-107568. A missing EPSS score is not a low risk. Compare the affected product with the linked advisory before you change production.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-862: Missing Authorization. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 19, 2026 · NIST NVD

    Detected

    Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows an authenticated user to send mail through the server as any address. A Sieve notify sends a notification message, and its :from tag names the sender; the server set the notification's From header to that :from as the script wrote i

  2. Oct 20, 2026 · NIST NVD

    Updated

    Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows an authenticated user to send mail through the server as any address. A Sieve notify sends a notification message, and its :from tag names the sender; the server set the notification's From header to that :from as the script wrote i

Sources

  • CVE.orgVulnerability recordCVE-2026-107568

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2026-107568

    Missing authorization in the Sieve notify action (6.2.22 through 6.3.6) and in the mail-rule Reply action (6.0.0 through 6.3.6) of Progressive Robot hMailServer allows an authenticated user to send mail through the server as any address. A Sieve notify sends a notification messag

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 20, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.