Your submission was sent successfully! Close

You have successfully unsubscribed! Close

Thank you for signing up for our newsletter!
In these regular emails you will find the latest updates about Ubuntu and upcoming events where you can meet our team.Close

CVE-2024-23185

Publication date 24 August 2024

Last updated 16 September 2024


Ubuntu priority

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.

Status

Package Ubuntu Release Status
dovecot 24.04 LTS noble
Fixed 1:2.3.21+dfsg1-2ubuntu6
22.04 LTS jammy
Fixed 1:2.3.16+dfsg1-3ubuntu2.4
20.04 LTS focal
Fixed 1:2.3.7.2-1ubuntu3.7
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
14.04 LTS trusty
Needs evaluation

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
dovecot

References

Related Ubuntu Security Notices (USN)

    • USN-6982-1
    • Dovecot vulnerabilities
    • 2 September 2024
    • USN-7013-1
    • Dovecot vulnerabilities
    • 16 September 2024

Other references