CVE-2026-26312
Stalwart Mail Server has Out-of-Memory Denial of Service via Malformed Nested MIME Messages
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
Stalwart is a mail and collaboration server. A denial-of-service vulnerability exists in Stalwart Mail Server versions 0.13.0 through 0.15.4 where accessing a specially crafted email containing malformed nested `message/rfc822` MIME parts via IMAP or JMAP causes excessive CPU and memory consumption, potentially leading to an out-of-memory condition and server crash. The malformed structure causes the `mail-parser` crate to produce cyclical references in its parsed representation, which Stalwart then follows indefinitely. Version 0.15.5 contains a patch.
| CWE | CWE-770 |
| Vendor | stalwartlabs |
| Product | stalwart |
| Published | Feb 19, 2026 |
| Last Updated | Feb 20, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
stalwartlabs / stalwart
>= 0.13.0, < 0.15.5