Improper Authentication in react-adal

Exploitation

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

CVSS

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

EPSS

• CVE-2020-7787: 1.28% estimated exploitation activity in the next 30 days; percentile 70.10 (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.

This affects versions of react-adal < 0.5.1. It is possible for a specially crafted JWT token and request URL can cause the nonce, session and refresh values to be incorrectly validated, causing the application to treat an attacker-generated JWT token as authentic. The logical defect is caused by how the nonce, session and refresh values are stored in the browser local storage or session storage. Each key is automatically appended by ||. When the received nonce and session keys are generated, the list of values is stored in the browser storage, separated by ||, with || always appended to the end of the list. Since || will always be the last 2 characters of the stored values, an empty string ("") will always be in the list of the valid values. Therefore, if an empty session parameter is provided in the callback URL, and a specially-crafted JWT token contains an nonce value of "" (empty string), then adal.js will consider the JWT token as authentic.

Published by the source

13 Apr 2021, 15:22 UTC

Last modified by the source

13 Mar 2026, 22:11 UTC

Source last checked

26 Oct 2026, 12:20 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7mpx-vg3c-cmr4

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7mpx-vg3c-cmr4

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# Patch Next advisory brief: CVE-2020-7787

Advisory: Improper Authentication in react-adal
IDs: CVE-2020-7787, GHSA-7mpx-vg3c-cmr4
Record: https://patchnext.com/advisories/cve-2020-7787 (revision 2, source checked 26 Oct 2026, 12:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: react-adal 0.5.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm react-adal: affected < 0.5.1; fixed in 0.5.1

## Suggested inspection (read-only)
- `npm ls react-adal --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 react-adal.
- 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-7mpx-vg3c-cmr4 (OSV record GHSA-7mpx-vg3c-cmr4 lists affected ranges: npm react-adal >=0 <0.5.1 (fixed))
- Verified: https://github.com/advisories/GHSA-7mpx-vg3c-cmr4 (GitHub-reviewed advisory GHSA-7mpx-vg3c-cmr4 lists affected ranges: npm react-adal >=0 <0.5.1)

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