Vulnerability in Cyrus IMAP (CVE-2026-47085)
Summary
Vulnerability in Cyrus IMAP (CVE-2026-47085). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.)
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-47085 has been found in Cyrus IMAP.
Risk of unauthorized operations or information disclosure. CVSS score: 4.0/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Cyrus IMAP CVE-2026-47085" on the vendor's site.
CVE-2026-47085 (Cyrus IMAP) — CWE-340 / CVSS v3 4.0
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-340) exists in Cyrus IMAP.
Check the vendor advisory for the affected versions of Cyrus IMAP.
Severity: Medium (CVSS 4.0/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Cyrus IMAP を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web cve@mitre.org
- web cve@mitre.org
- web nvd.nist.gov
- web github.com