Out-of-bounds Read in Cyrus Imap
CVE-2026-61908
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<emailid>-<index>, which could read past the end of the internal blob_headers array during download, exposing adjacent heap memory.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (12.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 12.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.002 · change: -0.002
Affected products
Weakness classification (CWE)
References
- cyrusimap.org (Product)
- www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html (Release Notes)
- www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html (Release Notes)
- www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html (Release Notes)
Frequently asked questions
- What is CVE-2026-61908?
- CVE-2026-61908 is a low-severity vulnerability in Cyrus Imap, classified under Out-of-bounds Read. CVSS score: 3.1/10. Published 2026-09-09.
- How severe is CVE-2026-61908?
- Low severity. CVSS v3 base score is 3.1 out of 10.