CVE-2020-26938

Name: CVE-2020-26938
Creator: NVD / NIST
Published: 2022-08-29T21:15:08.863+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.2/10EPSS 0.73%

Last modified Jun 17, 2026

CVE-2020-26938 is a high-severity vulnerability rated 7.2/10 on the CVSS scale. 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. EPSS estimates a 0.73% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.2/10

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

EPSS Probability

0.73%

49.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-601

Affected Software

Vendor	Product	Versions
Oauth2-Server Project	Oauth2-Server	<= 3.1.1

References

https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/grant-types/authorization-code-grant-type.js#L143Exploit, Third Party Advisory
https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/validator/is.js#L12Exploit, Third Party Advisory
https://github.com/oauthjs/node-oauth2-server/issues/637Issue Tracking, Third Party Advisory
https://tools.ietf.org/html/rfc3986#section-3Third Party Advisory
https://tools.ietf.org/html/rfc6749#section-3.1.2Third Party Advisory
https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/grant-types/authorization-code-grant-type.js#L143Exploit, Third Party Advisory
https://github.com/oauthjs/node-oauth2-server/blob/91d2cbe70a0eddc53d72def96864e2de0fd41703/lib/validator/is.js#L12Exploit, Third Party Advisory
https://github.com/oauthjs/node-oauth2-server/issues/637Issue Tracking, Third Party Advisory
https://tools.ietf.org/html/rfc3986#section-3Third Party Advisory
https://tools.ietf.org/html/rfc6749#section-3.1.2Third Party Advisory

Timeline

Published: Aug 29, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26938?

How severe is CVE-2020-26938?

CVE-2020-26938 has a CVSS score of 7.2/10 (HIGH severity). The EPSS model estimates a 0.73% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26938?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26938?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST