4.3

CVE-2026-61909: cyrus imap Unprotected Alternate Channel

CVSS: 4.3v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-61909DEBIAN-CVE-2026-61909
Published 09-09-2026Last modified 14-09-2026
Open JSON

Vulnerability summary

CVE-2026-61909 is a medium (CVSS 4.3) Unprotected Alternate Channel vulnerability in cyrus imap. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.8% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (NVD)
EPSS score
0.20%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:21929-1

Timeline

  1. 09-09-2026
    PublishedVulnerability first disclosed.
  2. 14-09-2026
    Last modifiedVulnerability information updated.

Description

An issue was discovered in Cyrus IMAP before 3.12.4. CalDAV/CardDAV multiget bypasses a per-href ACL. An authenticated DAV user with some shared access to another user's calendar or address book could read even unshared events or contacts by including the target hrefs in a calendar-multiget or addressbook-multiget REPORT.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.20%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

0.00 pp

From 0.20% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.20%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cyrus1 product
  • imap< 3.8.8 | ≥ 3.9.0, < 3.10.4 | ≥ 3.11.0, < 3.12.4
Cyrusimap1 product
  • cyrus_imap< 3.8.8 | ≥ 3.9.0, < 3.10.4 | ≥ 3.11.0, < 3.12.4
Debian1 product
  • cyrus-imapdAll versions (No fix recorded) | < 3.12.4-1
Ubuntu1 product
  • cyrus-imapdAll versions (No fix recorded)

4 vendors · 4 products

References

7 links