Cross Site Scripting vulnerability in usememos Memos v.0.26.0 allows a remote attacker to obtain sensitive information via the SANITIZESCHEMA, Memo Rendering Component, and Public/Private Memo View pages

A weakness has been identified in usememos memos up to 0.22.1. This affects the function memosaccesstoken of the file src/App.tsx of the component UpdateInstanceSetting. This manipulation of the argument additionalStyle/additionalScript causes improper authorization. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Incorrect access control in usememos memos v0.25.2 allows attackers with low-level privileges to arbitrarily modify or delete attachments made by other users.

Incorrect access control in usememos memos v0.25.2 allows attackers with low-level privileges to arbitrarily delete reactions made to other users' Memos.

Incorrect access control in the Identity Provider service of usememos memos v0.25.2 allows attackers with low-level privileges to arbitrarily modify or delete registered identity providers, leading to an account takeover or Denial of Service (DoS).

Incorrect access control in the /api/v1/user endpoint of usememos memos v0.25.2 allows unauthorized attackers to create arbitrary accounts via a crafted request.

A lack of file name validation or verification in the Attachment service of usememos memos v0.25.2 allows attackers to execute a path traversal.

Summary 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.

Impact

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.

Memos 0.22 is vulnerable to Stored Cross site scripting (XSS) vulnerabilities by the upload attachment and user avatar features. Memos does not verify the content type of the uploaded data and serve it back as is. An authenticated attacker can use this to elevate their privileges when the stored XSS is viewed by an admin.

When Memos 0.22 is configured to store objects locally, an attacker can create a file via the CreateResource endpoint containing a path traversal sequence in the name, allowing arbitrary file write on the server.

The Memos application, up to version v0.24.3, allows for the embedding of markdown images with arbitrary URLs. When a user views a memo containing such an image, their browser automatically fetches the image URL without explicit user consent or interaction beyond viewing the memo. This can be exploited by an attacker to disclose the viewing user's IP address, browser User-Agent string, and potentially other request-specific information to the attacker-controlled server, leading to information disclosure and user tracking.

elestio memos v0.23.0 is vulnerable to Server-Side Request Forgery (SSRF) due to insufficient validation of user-supplied URLs, which can be exploited to perform SSRF attacks.

A stored cross-site scripting (XSS) vulnerability was discovered in usememos/memos version 0.9.1. This vulnerability allows an attacker to upload a JavaScript file containing a malicious script and reference it in an HTML file. When the HTML file is accessed, the malicious script is executed. This can lead to the theft of sensitive information, such as login credentials, from users visiting the affected website. The issue has been fixed in version 0.10.0.

A CORS misconfiguration exists in memos where an arbitrary origin is reflected with Access-Control-Allow-Credentials set to true. This may allow an attacking website to make a cross-origin request, allowing the attacker to read private information or make privileged changes to the system as the vulnerable user account.

A CORS misconfiguration exists in memos where an arbitrary origin is reflected with Access-Control-Allow-Credentials set to true. This may allow an attacking website to make a cross-origin request, allowing the attacker to read private information or make privileged changes to the system as the vulnerable user account.

memos is a privacy-first, lightweight note-taking service. In memos 0.13.2, an SSRF vulnerability exists at the /api/resource that allows authenticated users to enumerate the internal network. Version 0.22.0 of memos removes the vulnerable file.

memos is a privacy-first, lightweight note-taking service. In memos 0.13.2, an SSRF vulnerability exists at the /o/get/httpmeta that allows unauthenticated users to enumerate the internal network and receive limited html values in json form. This vulnerability is fixed in 0.16.1.

memos is a privacy-first, lightweight note-taking service. In memos 0.13.2, an SSRF vulnerability exists at the /o/get/image that allows unauthenticated users to enumerate the internal network and retrieve images. The response from the image request is then copied into the response of the current server request, causing a reflected XSS vulnerability. Version 0.22.0 of memos removes the vulnerable file.

Cross-Site Request Forgery (CSRF) in GitHub repository usememos/memos prior to 0.15.1.

Improper Privilege Management in GitHub repository usememos/memos prior to 0.13.2.

Improper Input Validation in GitHub repository usememos/memos prior to 0.13.2.

Improper Access Control in GitHub repository usememos/memos prior to 0.13.2.

All versions of the package github.com/usememos/memos/server are vulnerable to Cross-site Scripting (XSS) due to insufficient checks on external resources, which allows malicious actors to introduce links starting with a javascript: scheme.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.10.0.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.10.0.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.10.0.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.10.0.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.10.0.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.10.0.

Cross-site Scripting (XSS) - Stored in GitHub repository usememos/memos prior to 0.9.1.