CVE-2026-3455 mailparser vulnerable to Cross-site Scripting
An attacker can execute arbitrary scripts in victim browsers via malicious URLs in emails parsed by the mailparser library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-3455?
CVE-2026-3455 is a medium-severity cross-site scripting vulnerability in mailparser, published on 3 Mar 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Versions of the package mailparser before 3.9.3 are vulnerable to Cross-site Scripting (XSS) via the textToHtml() function due to the improper sanitisation of URLs in the email content. An attacker can execute arbitrary scripts in victim browsers by adding extra quote " to the URL with embedded malicious JavaScript code.
Weakness: CWE-79
Which versions are affected by CVE-2026-3455?
2 open source packages ship an affected version, including mailparser. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
mailparser npm | All versions | 3.9.3 |
mailparser npm | All versions | 3.9.3 |
Products include Nodemailer Mailparser.
How do I fix CVE-2026-3455?
Upgrade mailparser to 3.9.3 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-3455 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-3455 exists.
Sources
Also known as GHSA-7gmj-h9xc-mcxc, MINI-rqcg-r4jq-pwx8.