CVE-2025-62380 Mailgen has HTML Injection and XSS Filter Bypass in Plaintext Emails
Attacker can inject HTML into plaintext emails via Unicode bypass, leading to script execution in victim's browser if rendered as HTML.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-62380?
CVE-2025-62380 is a low-severity cross-site scripting vulnerability in eladnava mailgen, published on 15 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
mailgen is a Node.js package that generates responsive HTML e-mails for sending transactional mail. Mailgen versions through 2.0.31 contain an HTML injection vulnerability in plaintext emails generated with the generatePlaintext method when user generated content is supplied. The plaintext generation code attempts to strip HTML tags using a regular expression and then decodes HTML entities, but tags that include certain Unicode line separator characters are not matched and removed. These encoded tags are later decoded into valid HTML content, allowing unexpected HTML to remain in output intended to be plaintext. Projects are affected if they call Mailgen.generatePlaintext with untrusted input and then render or otherwise process the returned string in a context where HTML is interpreted. This can lead to execution of attacker supplied script in the victim’s browser. Version 2.0.32 fixes the issue.
Weakness: CWE-79
Which versions are affected by CVE-2025-62380?
2 open source packages ship an affected version, including mailgen.
| Package | Affected | Fixed in |
|---|---|---|
mailgen npm | All versions | 2.0.32 |
mailgen npm | All versions | 2.0.32 |
How do I fix CVE-2025-62380?
Upgrade mailgen to 2.0.32 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-2025-62380 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62380 exists.
Sources
Also known as GHSA-q4w9-x3rv-4c8j.