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MEDIUM severity

mailparser vulnerable to Cross-site ScriptingGHSA-7gmj-h9xc-mcxc

MEDIUMFix: nodemailer/mailparser@921a67d

GHSA-7gmj-h9xc-mcxc is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in mailparser. A fix is available for mailparser — see the affected versions and patch details below.

Also known asCVE-2026-3455
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for GHSA-7gmj-h9xc-mcxc.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs30th percentile — riskier than 30% of all scored CVEsHighest risk
0.00%0.31%0.62%0.93%0.0%0.4%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

1Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream
mailparsernpm
8.1Mdownloads / week

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmmailparserall versions3.9.3npm install mailparser@3.9.3

Affected Products

1 product · 1 configurations
Application
mailparsernodemailer
< 3.9.3
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mailparser, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update mailparser to 3.9.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7gmj-h9xc-mcxc is resolved across your whole dependency graph.

  3. Workarounds

    Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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mailparser vulnerable to Cross-site Scripting (Medium 6.1)