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📦 npm

CVE-2025-62380

Mailgen has HTML Injection and XSS Filter Bypass in Plaintext Emails

Also known asGHSA-q4w9-x3rv-4c8j
Published
Oct 15, 2025
Updated
Apr 2, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk32th percentile+0.28%
0.00%0.30%0.61%0.91%0.1%0.4%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

mailgennpm
13Kdownloads / week

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmmailgenall versions2.0.32

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mailgen. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update mailgen to 2.0.32 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-62380 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2025-62380 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2025-62380. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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 intend
O3 Security · Impact-Aware SCA

Is CVE-2025-62380 in your dependencies?

O3 detects CVE-2025-62380 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.