CVE-2024-45800

What it is

Snappymail is an open source web-based email client. SnappyMail uses the `cleanHtml()` function to cleanup HTML and CSS in emails. Research discovered that the function has a few bugs which cause an mXSS exploit. Because the function allowed too many (invalid) HTML elements, it was possible (with incorrect markup) to trick the browser to "fix" the broken markup into valid markup. As a result a motivated attacker may be able to inject javascript. However, due to the default Content Security Policy the impact of the exploit is minimal. It could be possible to create an attack which leaks some data when loading images through the proxy. This way it might be possible to use the proxy to attack the local system, like with `http://localhost:5000/leak`. Another attack could be to load a JavaScript attachment of the email. This is very tricky as the email must link to every possible UID as each email has a unique UID which has a value between 1 and 18446744073709551615 **v2.38.0** and up now remove unsupported HTML elements which mitigates the issue. Users are advised to upgrade. Older versions can install an extension named "Security mXSS" as a mitigation. This will be available at the administration area at `/?admin#/packages`. **NOTE:** this extension can not "fix" malicious code in encrypted messages or (html) attachments as it can't manipulate the JavaScript code for this. It only protects normal message HTML.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2024-09-16 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 07:54 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 5.0 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2024-09-16 20:15 UTC

Last modified

2026-06-17 07:54 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-79 · Cross-site scripting

Record status

Deferred

Attack profile CVSS 3.1 · 5.0

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2024-45800.md and follow it. Check whether this project is affected by CVE-2024-45800. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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