Medium severity · published Sep 9, 2026
CVE-2026-61908
An issue was discovered in Cyrus IMAP before 3.12.4
6.5
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 13% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CI
Cyrus IMAP · cyrusimap
before 3.8.8; 3.9.0 before 3.10.4; 3.11.0 before 3.12.4 · source: vendor
IM
Imap · Cyrus
before 3.8.8; 3.9.0 before 3.10.4; 3.11.0 before 3.12.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-61908
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-61908
Product
https://cyrusimap.org
Release Notes
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html
Release Notes
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html
Release Notes
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html
More from Cyrus IMAP
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CVE-2026-61915
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6.5
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6.5
CVE-2024-34055
Cyrus IMAP before 3.8.3 and 3.10.x before 3.10.0-rc1 allows authenticated attackers to cause unbounded memory allocation by sending many LITERALs in a single command
6.5
CVE-2017-12843
Cyrus IMAP before 3.0.3 allows remote authenticated users to write to arbitrary files via a crafted (1) SYNCAPPLY, (2) SYNCGET or (3) SYNCRESTORE command
5.4
CVE-2026-47082
An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2