Out-of-Bounds Read in Cyrus IMAP (CVE-2026-61908)
Summary
Vulnerability in Cyrus IMAP (CVE-2026-61908). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
An issue was discovered in Cyrus IMAP before 3.12.4. A JMAP email-header blob ID can reference an out-of-bounds index. An authenticated user could attempt to download a crafted JMAP blob ID of the form H-, which could read past the end of the internal blob_headers array during download, exposing adjacent heap memory.
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-2026-61908 has been found in Cyrus IMAP.
Risk of unauthorized operations or information disclosure. CVSS score: 3.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Cyrus IMAP CVE-2026-61908" on the vendor's site.
CVE-2026-61908 (Cyrus IMAP) — CWE-125 / CVSS v3 3.1
Attack vector: remote (network-reachable) / 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.
Out-of-bounds read (CWE-125) exists in Cyrus IMAP.
Check the vendor advisory for the affected versions of Cyrus IMAP.
Severity: Low (CVSS 3.1/10). 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。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-61908 cyrus-imapd
- Ubuntu UBUNTU-CVE-2026-61908 cyrus-imapd
References
- web cyrusimap.org
- web cyrusimap.org
- web cyrusimap.org
- web cyrusimap.org
- web nvd.nist.gov
- web github.com