CVE-2026-61908

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-09 · updated 2026-09-16
Weakness: CWE-125

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.

Affected products

cyrusimap Cyrus IMAP: before 3.8.8; from 3.9.0 before 3.10.4; from 3.11.0 before 3.12.4 — fixed in 3.10.4, 3.12.4, 3.8.8

How to fix

Upgrade to a fixed version: cyrusimap Cyrus IMAP 3.10.4, 3.12.4, 3.8.8. Check the vendor advisory for mitigations.

References

https://cyrusimap.org
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html
https://www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html

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