7.5
HIGH
CVE-2024-23185
Dovecot Message Header Buffer Overload Vulnerability
Description

Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions. Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly available exploits are known.

INFO

Published Date :

Sept. 10, 2024, 3:15 p.m.

Last Modified :

Nov. 21, 2024, 8:57 a.m.

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

3.9
Affected Products

The following products are affected by CVE-2024-23185 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2024-23185.

URL Resource
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2024/oxdc-adv-2024-0003.json
http://seclists.org/fulldisclosure/2024/Aug/18
http://www.openwall.com/lists/oss-security/2024/08/15/4

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2024-23185 vulnerability anywhere in the article.

  • seclists.org
Dovecot CVE-2024-23185: Very large headers can cause resource exhaustion when parsing message

Full Disclosure mailing list archives From: Aki Tuomi via Fulldisclosure <fulldisclosure () seclists org> Date: Wed, 14 Aug 2024 14:13:42 +0300 (EEST) Affected product: Dovecot IMAP Server Internal re ... Read more

Published Date: Aug 18, 2024 (4 months, 1 week ago)

The following table lists the changes that have been made to the CVE-2024-23185 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference http://seclists.org/fulldisclosure/2024/Aug/18
    Added Reference http://www.openwall.com/lists/oss-security/2024/08/15/4
  • CVE Received by [email protected]

    Sep. 10, 2024

    Action Type Old Value New Value
    Added Description Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions. Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly available exploits are known.
    Added Reference Open-Xchange https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2024/oxdc-adv-2024-0003.json [No types assigned]
    Added CWE Open-Xchange CWE-770
    Added CVSS V3.1 Open-Xchange AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2024-23185 is associated with the following CWEs:

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability