CVE-2024-21635: memos Auth Bypass — Exploit & Fix

Description

Memos is a privacy-first, lightweight note-taking service that uses Access Tokens to authenticate application access. When a user changes their password, the existing list of Access Tokens stay valid instead of expiring. If a user finds that their account has been compromised, they can update their password. In versions up to and including 0.18.1, though, the bad actor will still have access to their account because the bad actor's Access Token stays on the list as a valid token. The user will have to manually delete the bad actor's Access Token to secure their account. The list of Access Tokens has a generic Description which makes it hard to pinpoint a bad actor in a list of Access Tokens. A known patched version of Memos isn't available. To improve Memos security, all Access Tokens will need to be revoked when a user changes their password. This removes the session for all the user's devices and prompts the user to log in again. One can treat the old Access Tokens as "invalid" because those Access Tokens were created with the older password.

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CVSS v3.1 Score

7.5

HIGH

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

Weakness Type (CWE)

CWE-287 Improper Authentication

Affected Products

Vendor	Product	Versions
usememos	memos	< 0.18.1

References

Advisories & Patches

https://github.com/usememos/memos/security/advisories/GHSA-mr34-8733-grr2 https://github.com/usememos/memos/security/advisories/GHSA-mr34-8733-grr2

Exploits

https://github.com/usememos/memos/security/advisories/GHSA-mr34-8733-grr2 https://github.com/usememos/memos/security/advisories/GHSA-mr34-8733-grr2

Frequently Asked Questions

What is CVE-2024-21635? +

Memos is a privacy-first, lightweight note-taking service that uses Access Tokens to authenticate application access. When a user changes their password, the existing list of Access Tokens stay valid instead of expiring. If a user finds that their account has been compromised, they can update their password. In versions up to and including 0.18.1, though, the bad actor will still have access to their account because the bad actor's Access Token stays on the list as a valid token. The user will have to manually delete the bad actor's Access Token to secure their account. The list of Access Tokens has a generic Description which makes it hard to pinpoint a bad actor in a list of Access Tokens. A known patched version of Memos isn't available. To improve Memos security, all Access Tokens will need to be revoked when a user changes their password. This removes the session for all the user's devices and prompts the user to log in again. One can treat the old Access Tokens as "invalid" because those Access Tokens were created with the older password. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2024-21635? +

CVE-2024-21635 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2024-21635? +

CVE-2024-21635 affects products from usememos, specifically: memos. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-21635? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2024-21635