CVE-2025-62366 Mailgen vulnerable to HTML injection and cross-site scripting via plaintext email generation
Attacker can execute JavaScript via HTML injection in plaintext emails if rendered as HTML, affecting users of the mailgen Node.js library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-62366?
CVE-2025-62366 is a low-severity cross-site scripting vulnerability in eladnava mailgen, published on 14 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 2.0.30 contain an HTML injection vulnerability in plaintext emails produced by the generatePlaintext method when user‑generated content is supplied. The function attempts to remove HTML tags, but if tags are provided as encoded HTML entities they are not removed and are later decoded, resulting in active HTML (for example an img tag with an event handler) in the supposed plaintext output. In contexts where the generated plaintext string is subsequently rendered as HTML, this can allow execution of attacker‑controlled JavaScript. Versions 2.0.31 and later contain a fix. No known workarounds exist.
Weakness: CWE-79
Which versions are affected by CVE-2025-62366?
2 open source packages ship an affected version, including mailgen.
| Package | Affected | Fixed in |
|---|---|---|
mailgen npm | All versions | 2.0.31 |
mailgen npm | All versions | 2.0.31 |
How do I fix CVE-2025-62366?
Upgrade mailgen to 2.0.31 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-2025-62366 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62366 exists.
Sources
Also known as GHSA-xw6r-chmh-vpmj.