Regular Expression Denial of Service in npm-user-validate

Exploitation

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

CVSS

not scored

EPSS

• CVE-2020-7754: 3.48% estimated exploitation activity in the next 30 days; percentile 89.13 (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.

npm-user-validate before version 1.0.1 is vulnerable to a Regular Expression Denial of Service (REDos). The regex that validates user emails took exponentially longer to process long input strings beginning with @ characters. Impact The issue affects the email function. If you use this function to process arbitrary user input with no character limit the application may be susceptible to Denial of Service. Patches The issue is patched in version 1.0.1 by improving the regular expression used and also enforcing a 254 character limit. Workarounds Restrict the character length to a reasonable degree before passing a value to .emal(); Also, consider doing a more rigorous sanitizing/validation beforehand.

Published by the source

10 May 2021, 19:08 UTC

Last modified by the source

8 Jul 2026, 06:49 UTC

Source last checked

26 Oct 2026, 12:15 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-xgh6-85xh-479p

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-xgh6-85xh-479p

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-pw54-mh39-w3hc

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# Patch Next advisory brief: CVE-2020-7754

Advisory: Regular Expression Denial of Service in npm-user-validate
IDs: CVE-2020-7754, GHSA-pw54-mh39-w3hc
Record: https://patchnext.com/advisories/cve-2020-7754 (revision 3, source checked 26 Oct 2026, 12:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: npm-user-validate 1.0.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm npm-user-validate: affected <= 1.0.0; fixed in 1.0.1

## Suggested inspection (read-only)
- `npm ls npm-user-validate --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 npm-user-validate.
- 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-pw54-mh39-w3hc (OSV record GHSA-pw54-mh39-w3hc lists affected ranges: npm npm-user-validate >=0 <1.0.1 (fixed))
- Verified: https://osv.dev/vulnerability/GHSA-xgh6-85xh-479p (OSV record GHSA-xgh6-85xh-479p lists affected ranges: npm npm-user-validate >=0 <1.0.1 (fixed))
- Verified: https://github.com/advisories/GHSA-xgh6-85xh-479p (GitHub-reviewed advisory GHSA-xgh6-85xh-479p lists affected ranges: npm npm-user-validate >=0 <=1.0.0)

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