stalwartlabs stalwart up to 0.15.4 Email allocation of resources

Summaryinfo

A vulnerability described as problematic has been identified in stalwartlabs stalwart up to 0.15.4. This affects an unknown part of the component Email Handler. Such manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2026-26312. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in stalwartlabs stalwart up to 0.15.4. It has been rated as problematic. Affected by this issue is an unknown code block of the component Email Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-26312 since 02/13/2026. The exploitation is known to be easy. The attack may be launched remotely. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 0.15.5 eliminates this vulnerability.

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Productinfo

Vendor

• stalwartlabs

Name

• stalwart

Version

• 0.15.0
• 0.15.1
• 0.15.2
• 0.15.3
• 0.15.4

Website

• Product: https://github.com/stalwartlabs/stalwart/

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