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CVE-2026-47085: cyrusimap cyrus_imap

CVSS: 4.0v3.1MediumDeferred
AliasesUBUNTU-CVE-2026-47085DEBIAN-CVE-2026-47085
Published 16-07-2026Last modified 16-07-2026
Open JSON

Vulnerability summary

CVE-2026-47085 is a medium (CVSS 4.0) vulnerability in cyrusimap cyrus_imap. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 21% of scored vulnerabilities.

Overall risk
16/100
0100
Low · default modelHow is this calculated?
CVSS score
4.0/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.30%
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-2026:21368-1

Timeline

  1. 16-07-2026
    PublishedVulnerability first disclosed.
  2. 16-07-2026
    Last modifiedVulnerability information updated.

Description

An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. URLAUTH token forgery can occur via a missing mboxkey. If an attacker knew a folder name on the victim's account for which the victim had never issued an auth URL, they could forge a working URLAUTH token by computing an HMAC-SHA1 value with a predictable key, giving them read access to the mailbox. (URLAUTH is an obscure feature, meaning that the odds of any user actually being susceptible to this attack are very low. Perhaps no public clients use URLAUTH.)

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.30%

Chance of exploitation in the next 30 days

Percentile

21%

Versus all other CVEs

30-day change

0.00 pp

From 0.30% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.30%

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

Cyrusimap1 product
Debian1 product
  • cyrus-imapd< 3.6.1-4+deb12u5 | < 3.10.2-1+deb13u2 | < 3.12.3-1
Ubuntu1 product
  • cyrus-imapdAll versions (No fix recorded)

3 vendors · 3 products

References

5 links