Nodemailer jsonTransport bypasses disableFileAccess and disableUrlAccess during message normalization

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.4 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS

• CVE-2026-82660: 0.26% estimated exploitation activity in the next 30 days; percentile 17.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Nodemailer's disableFileAccess and disableUrlAccess options are intended to prevent message content and attachments from reading local files or fetching URLs. The normal MIME streaming path enforces those options in MimeNode.getStream(). However, jsonTransport serializes messages by calling mail.normalize(), which resolves html, text, alternatives, calendar events, and attachments through shared.resolveContent() before MIME generation. shared.resolveContent() reads local files and fetches HTTP(S) URLs directly, without receiving or checking disableFileAccess or disableUrlAccess. As a result, applications that use jsonTransport as a safe serializer or queue payload generator while relying on disableFileAccess / disableUrlAccess can still be made to read local files into the generated JSON output or make outbound HTTP requests when an attacker controls message content fields such as attachment path or text.href. The same missing-enforcement root cause is also reachable before…

Published by the source

15 Jun 2026, 17:35 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-wqvq-jvpq-h66f

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-wqvq-jvpq-h66f

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-82660

Advisory: Nodemailer jsonTransport bypasses disableFileAccess and disableUrlAccess during message normalization
IDs: CVE-2026-82660, GHSA-wqvq-jvpq-h66f
Record: https://patchnext.com/advisories/cve-2026-82660 (revision 2, source checked 26 Oct 2026, 12:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: nodemailer 8.0.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm nodemailer: affected <= 8.0.8; fixed in 8.0.9

## Suggested inspection (read-only)
- `npm ls nodemailer --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on nodemailer.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-wqvq-jvpq-h66f (OSV record GHSA-wqvq-jvpq-h66f lists affected ranges: npm nodemailer >=0 <8.0.9 (fixed))
- Verified: https://github.com/advisories/GHSA-wqvq-jvpq-h66f (GitHub-reviewed advisory GHSA-wqvq-jvpq-h66f lists affected ranges: npm nodemailer >=0 <=8.0.8)

Commands are suggestions: review each one before running it.