Unbounded Memory Allocation Vulnerability in Stalwart Mail Server
CVE-2025-61600

7.5HIGH

Key Information:

Vendor

Stalwartlabs

Status
Stalwart
Vendor
CVE Published:
2 October 2025

What is CVE-2025-61600?

The Stalwart Mail and Collaboration Server is susceptible to an unbounded memory allocation vulnerability within its IMAP protocol parser. This issue arises from several state handlers that fail to enforce size limits on dynamic buffers, allowing remote attackers to exploit this flaw. By sending specially crafted requests, attackers can exhaust server memory resources, potentially triggering the system's out-of-memory (OOM) killer, which leads to service outages. While version 0.13.4 addresses this vulnerability, administrators are encouraged to adopt rate limiting and connection monitoring strategies at the network level as interim protective measures.

Affected Version(s)

stalwart < 0.13.4

References

https://github.com/stalwartlabs/stalwart/security/advisor...
x_refsource_CONFIRM
https://github.com/stalwartlabs/stalwart/commit/a8e631e88...
x_refsource_MISC
https://github.com/stalwartlabs/stalwart/releases/tag/v0....
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2025-61600 : Unbounded Memory Allocation Vulnerability in Stalwart Mail Server