CVE-2024-23185

A security issue was found in Dovecot. Very large headers can lead to resource exhaustion when parsing messages. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to the message-header-parser, it starts building up a "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit so large headers can cause large memory usage. This issue occurs whether it is a single long header line or a single header split into multiple lines.

This vulnerability is considered moderate rather than important because, while it can lead to resource exhaustion through unbounded memory allocation, its exploitability is limited by several factors. Incoming mail typically passes through an MTA that enforces size limits, significantly reducing the likelihood of an external attacker successfully exploiting the issue. Additionally, the potential for a user to cause a denial-of-service (DoS) attack on themselves by appending large emails is largely self-contained, affecting only the user's session and not posing a broader systemic risk. As a result, the overall impact is mitigated, making it a moderate severity issue.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.