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Fencer Vulns
medium 4.0

CVE-2026-47085 json

An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2.

published 2026-07-16 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-45008

cvss
4.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

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.)

Patch / fix

  • cyrusimap Cyrus IMAP 3.12.3
  • cyrus-imapd Debian 12 3.6.1-4+deb12u5
  • cyrus-imapd Debian 13 3.10.2-1+deb13u2
  • cyrus-imapd Debian 14 3.12.3-1

debian advisories DEBIAN-CVE-2026-47085

  • cyrus-imapd openSUSE Leap 16.0 3.8.7-bp160.1.1

opensuse advisories openSUSE-SU-2026:21368-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-47085 updated cvss 4.0

cyrus-imapd: Cyrus IMAP: Information disclosure via URLAUTH token forgery

  • Red Hat Enterprise Linux 6 cyrus-imapd, cyrus-imapd-utils Red Hat Enterprise Linux 7 cyrus-imapd, cyrus-imapd-utils
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 cyrus-imapd, cyrus-imapd-vzic, cyrus-imapd-utils Red Hat Enterprise Linux 9 perl-Cyrus, cyrus-imapd, cyrus-imapd-libs, cyrus-imapd-utils Red Hat Enterprise Linux 10 cyrus-imapd
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

Affected products

  • cyrusimap Cyrus IMAP

Classification

Weakness
  • CWE-340 Generation of Predictable Numbers or Identifiers

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.