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CVE-2026-61909VulnerabilityPublished 09/09/2026Updated 09/14/2026

CVE-2026-61909: cyrusimap Cyrus IMAP · Unprotected Alternate Channel

Affects cyrusimap Cyrus IMAPSource CVE Database V5

0

Not known to be exploited · CVSS 3.5 Medium.

Data as of 10/25/2026, 16:58:56 UTC

CVSS 3.1 base score
3.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

What to do

Affected software

ProductAffectedFixed in
cyrusimapCyrus IMAPAffected
  • <3.8.8
  • >=3.9.0 <3.10.4
  • >=3.11.0 <3.12.4
Fixed in
  • 3.8.8
  • 3.10.4
  • 3.12.4

AI-suggested

No explicit patch links are provided in the input data. Until a patch is applied, restrict authenticated DAV user permissions carefully to minimize shared access scope. Monitor vendor communications for official fixes and apply updates when available.

Description

CVE-2026-61909 is a medium severity vulnerability in Cyrus IMAP before version 3.12.4. It involves a CalDAV/CardDAV multiget operation bypassing per-href access control lists (ACLs). An authenticated DAV user with some shared access to another user's calendar or address book could read unshared events or contacts by including target hrefs in a calendar-multiget or addressbook-multiget REPORT.

Impact

The impact is limited to confidentiality loss of calendar events or contacts that are not shared with the attacker but belong to another user. There is no impact on integrity or availability. The attacker must be authenticated with some level of shared access to the victim's calendar or address book. The CVSS score is 3.5 (medium), reflecting the low complexity of exploitation but limited impact scope.

Weaknesses

References

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