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CVE-2026-61911VulnerabilityPublished 09/09/2026Updated 09/10/2026

CVE-2026-61911: CWE-497 Exposure of Sensitive System Information to an Unauthorized Control Sphere in cyrusimap Cyrus IMAP

Affects cyrusimap Cyrus IMAPSource CVE Database V5

0

Not known to be exploited · CVSS 4.3 Medium · fixed in 3.12.4 : update cyrusimap Cyrus IMAP when convenient.

Data as of 10/25/2026, 04:40:13 UTC

CVSS 3.1 base score
4.3Medium
How severe the flaw is on the 0–10 CVSS scale.
Exploitation

Not in CISA KEV, no exploitation reported

EPSS
0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 3.12.4
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

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

A fix is available in Cyrus IMAP version 3.12.4. Users should upgrade to version 3.12.4 or later to remediate this vulnerability. No vendor advisory was provided to indicate alternative mitigations or that no action is required.

Description

CVE-2026-61911 is a medium severity vulnerability in Cyrus IMAP before version 3.12.4. It allows an authenticated user to leverage a Sieve script to detect the existence of another user's private mailbox or read shared mailbox annotations by observing LMTP delivery behavior. This vulnerability exposes sensitive system information but does not permit modification or denial of service.

Impact

The vulnerability exposes sensitive system information about mailbox existence and shared mailbox annotations to authenticated users. This information disclosure could facilitate further reconnaissance by an attacker but does not directly enable data modification or denial of service.

Weaknesses

References

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