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CVE Record

CVE-2020-26938: In oauth2-server (aka node-oauth2-server) through 3.1.1, the value of the redirect_uri parameter received d...

In oauth2-server (aka node-oauth2-server) through 3.1.1, the value of the redirect_uri parameter received during the authorization and token request is checked against an incorrect URI pattern ("[a-zA-Z][a-zA-Z0-9+.-]+:") before making a redirection. This allows a malicious client to pass an XSS payload through the redirect_uri parameter while making an authorization request. NOTE: this vulnerability is similar to CVE-2020-7741.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Applications using node-oauth2-server through 3.1.1 may mishandle redirect_uri validation in OAuth flows. A malicious OAuth client could submit a crafted redirect URI that is accepted and used in a redirect, enabling cross-site scripting in affected authorization flows. Business impact depends on whether the library is exposed in login or authorization endpoints.

Executive priority

Medium priority unless the vulnerable library backs public authentication flows. If exposed on customer-facing OAuth endpoints, prioritize review and remediation because XSS in login or authorization paths can undermine user trust and session security. Evidence is insufficient to claim active exploitation or a universal emergency.

Technical view

The CVE describes oauth2-server/node-oauth2-server through 3.1.1 using an incorrect URI scheme pattern when validating redirect_uri during authorization and token requests before redirection. That validation can allow an XSS payload in redirect_uri during authorization requests. Sources do not provide CVSS, CWE, patch version, or exploit-in-the-wild evidence.

Likely exposure

Exposure is limited to systems that directly use oauth2-server, also called node-oauth2-server, through version 3.1.1 and expose OAuth authorization or token flows accepting redirect_uri. The bundle lists affected vendor and product as n/a, so inventory should focus on package usage and deployed services rather than CPE matching.

Exploitation context

The source bundle states the issue can be triggered by a malicious client using redirect_uri in an authorization request. It does not cite active exploitation, and KEV status is false. Treat this as plausible web-facing risk when affected OAuth endpoints are internet-accessible, but do not assume exploitation without additional evidence.

Researcher notes

Key evidence is the CVE description and linked project code references showing redirect_uri validation and authorization-code flow handling. Affected versions are stated as through 3.1.1, but the bundle does not name a fixed release. Validate exposure through dependency inventory and OAuth route behavior, not CPE data.

Mitigation direction

  • Identify deployments using oauth2-server or node-oauth2-server through 3.1.1.
  • Check the upstream project issue and vendor guidance for fixed versions or migration advice.
  • Restrict OAuth clients and allowed redirect URIs to known trusted values.
  • Review authorization endpoints for reflected redirect_uri handling and XSS exposure.
  • Prioritize remediation for internet-facing login and consent flows.

Validation and detection

  • Search application dependency manifests for oauth2-server or node-oauth2-server versions through 3.1.1.
  • Map services exposing OAuth authorization or token endpoints using this library.
  • Verify redirect_uri validation follows RFC 6749 expectations for registered redirection endpoints.
  • Confirm untrusted redirect_uri values are not reflected into browser-executed contexts.
  • Document whether any compensating controls restrict malicious client registration.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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description · low confidence lookup

Credential and access behavior lookup

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cve · low confidence lookup

CVE-2020-26938 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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