CVE-2024-21635

Access Tokens are used 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.

The bad actor though 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.

Details

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. You can treat the old Access Tokens as "invalid" because those Access Tokens were created with the older password.

PoC

1. Have 2 devices on hand
2. Log onto your Memos account on both devices. Notice how Access Tokens are created for each.
3. On one device, successfully change the password. Refresh the page on the 2nd device and notice how it doesn't log out the user.
4. On the 2nd device, change the password again. Refresh the page on the 1st device and notice how it doesn't log out the user.

A bad actor will still have access to the user's account because the Access Token does not expire on a password update. Having multi-factor authentication will vastly improve account security in Account Takeover cases instead of just relying on a password.

The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.

Kodem intelligence

1. What is CVE-2024-21635? CVE-2024-21635 is a high-severity improper authentication vulnerability in github.com/usememos/memos (go), affecting versions <= 0.18.1. It is fixed in 0.18.2. The application does not adequately verify the identity of a user, device, or process before granting access.
2. Which versions of github.com/usememos/memos are affected by CVE-2024-21635? github.com/usememos/memos (go) versions <= 0.18.1 is affected.
3. Is there a fix for CVE-2024-21635? Yes. CVE-2024-21635 is fixed in 0.18.2. Upgrade to this version or later.
4. Is CVE-2024-21635 exploitable, and should I be worried? Whether CVE-2024-21635 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2024-21635 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2024-21635? Upgrade github.com/usememos/memos to 0.18.2 or later.