CVE-2021-29437

MEDIUMCVSS 6.8/10EPSS 0.81%

Last modified

CVE-2021-29437 is a medium-severity vulnerability rated 6.8/10 on the CVSS scale. 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. EPSS estimates a 0.81% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
6.8/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS Probability
0.81%

52.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
Scratchoauth2 ProjectScratchoauth2< 2021-04-13

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-29437?
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.
How severe is CVE-2021-29437?
CVE-2021-29437 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.81% probability of exploitation in the next 30 days.
How do I fix CVE-2021-29437?
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-2021-29437?

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

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Source: NVD / NIST