CVE-2026-47082Network attack vector

Authenticated mailbox writes via skipped destination ACL

Published Jul 16, 2026 · Updated Jul 16, 2026

Incorrect authorization in Cyrus IMAP before 3.12.3 allows remote authenticated users to write vacation replies into arbitrary mailboxes. The vacation Sieve :fcc path delivers a saved copy without checking the destination mailbox's insert ACL. Exploitation requires an authenticated user able to install a vacation Sieve script and modifies mailbox contents without granted insert permission.

CVSS severity5.4
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Cyrus IMAP before 3.12.3 allows remote authenticated users to write vacation replies into arbitrary mailboxes. The vacation Sieve :fcc path delivers a saved copy without checking the destination mailbox's insert ACL. Exploitation requires an authenticated user able to install a vacation Sieve script and modifies mailbox contents without granted insert permission.

The record

CVE
CVE-2026-47082
Published
Jul 16, 2026
Updated
Jul 16, 2026
Vendor
Project Cyrus
Product
Cyrus IMAP
Classifications
CWE-863, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.12.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Project Cyrus · Cyrus IMAPversion=0 <3.12.3

Published CVSS scores

5.4MITRECVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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