Is CVE-2021-29437 actively exploited?

No active exploitation of CVE-2021-29437 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-29437 be exploited remotely?

Yes. CVE-2021-29437 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-29437?

CVE-2021-29437 has a CVSS score of 6.8 (MEDIUM).

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MEDIUM

CVE-2021-29437

CWE-863Published: April 13, 2021· Updated: Jun 17, 2026

6.8

CVSS v3.1

Official Description

ScratchOAuth2 is an Oauth implementation for Scratch. Any ScratchOAuth2-related data normally accessible and modifiable by a user can be read and modified by a third party. 1. Scratch user visits 3rd party site. 2. 3rd party site asks user for Scratch username. 3. 3rd party site pretends to be user and gets login code from ScratchOAuth2. 4. 3rd party site gives code to user and instructs them to post it on their profile. 5. User posts code on their profile, not knowing it is a ScratchOAuth2 login code. 6. 3rd party site completes login with ScratchOAuth2. 7. 3rd party site has full access to anything the user could do if they directly logged in. See referenced GitHub security advisory for patch notes and workarounds.

NVD Source

Technical Analysis

CVE-2021-29437 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 6.8.