Memos before 0.27.0 Missing Authorization via ActivityService ListActivities/GetActivity

Memos before 0.27.0 contains a missing authorization vulnerability in the ActivityService ListActivities and GetActivity API methods that allows authenticated users to view all users' activity records. Low-privileged attackers can enumerate sequential activity IDs to obtain creator IDs, timestamps, and memo-comment references, including activity on other users' private memos.

Memos 0.26.0 through 0.30.0 Insufficient Session Expiration on Password Change

Memos versions 0.26.0 through 0.30.0 fail to revoke refresh tokens when a user changes their password, allowing attackers to maintain account access. An attacker with a stolen refresh token can call the RefreshToken RPC to obtain new access tokens and rotate the refresh token indefinitely, bypassing the password change security measure.

Memos through 0.30.0 SSRF via Omitted CGNAT Address Range

Memos through 0.30.0 omits the 100.64.0.0/10 carrier-grade NAT address range from SSRF protection in its link-metadata fetcher, allowing unauthenticated attackers to bypass IP validation. Attackers can make the server request internal hosts in that range including cloud metadata services and read page titles and descriptions back.

SSO Authentication Bypass Allows Account Takeover in UseMemos 0.27.1

An issue in usememos v0.27.1 allows a remote attacker to achieve account takeover via the ssoCredentials branch of the SignIn handler in server/router/api/v1/auth_service.go, because SSO identity is matched only on an attacker-controllable identifier without binding to the IdP's stable subject claim.

An issue in usememos through v0.30.0 allows a remote authenticated attacker to perform Server-Side Request Forgery (SSRF) via the Webhook validation mechanism in internal/webhook/validate.go, by setting a webhook target to an internal address.

Memos Webhook DNS Rebinding TOCTOU SSRF in safeDialContext()

Memos' webhook dispatch function safeDialContext (internal/webhook/webhook.go) resolves the target hostname via net.DefaultResolver.LookupHost and validates the resulting IPs against reserved ranges, but then dials net.JoinHostPort(host, port) using the original hostname rather than the already-validated IP address.

Memos Webhook SSRF via 0.0.0.0 Reserved-IP Bypass

Memos' webhook URL validation, isReservedIP (internal/webhook/validate.go), checks a candidate IP against a reservedCIDRs list that omits 0.0.0.0/8 and never calls ip.IsUnspecified — unlike the correctly implemented sibling function isInternalIP in internal/httpgetter/html_meta.go, which does.

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

usememos UpdateInstanceSetting App.tsx memos_access_token improper authorization

A weakness has been identified in usememos memos up to 0.22.1. This affects the function memos_access_token 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 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 usememos memos v0.25.2 allows attackers with low-level privileges to arbitrarily delete reactions made to other users' Memos.

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 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.

Memos Access Tokens Stay Valid after User Password Change

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.

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.

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.

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.

GHSL-2024-034: memos CORS Misconfiguration in server.go

memos is a privacy-first, lightweight note-taking service. A CORS misconfiguration exists in memos 0.20.1 and earlier 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. This vulnerability is fixed in 0.21.0.