CVE-2025-50738: Memos Application Exposes User Information Through Markdown Images
The Memos application, a popular open-source note-taking platform, has a vulnerability that could expose sensitive user information. By embedding specially crafted Markdown images, attackers can track users without their explicit consent.
Vulnerability Details
- CVE ID: CVE-2025-50738
- Description: The Memos application (up to version v0.24.3) allows embedding Markdown images with arbitrary URLs. Simply viewing a memo with such an image triggers the browser to fetch the URL, inadvertently sending the user's IP address, User-Agent, and other request headers to the attacker's server.
- CVSS Score: 9.8 (Critical)
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CVSS Explanation:
This vulnerability receives a critical score because it's remotely exploitable, requires no user interaction, and can lead to complete compromise of confidentiality, integrity, and availability. An attacker can easily gather significant information about users simply by having them view a memo.
- Exploit Requirements: An attacker needs to create a memo containing a Markdown image with a URL pointing to their server and then convince a user to view that memo.
- Affected Vendor: usememos
- Affected Product: Memos
- Affected Version: Up to v0.24.3
- CWE: CWE-200 - Information Exposure. This means the application unintentionally reveals sensitive data to unauthorized parties. In this case, it's the user's IP address and User-Agent string.
Timeline of Events
- Discovered: Unknown
- Reported: Unknown
- CVE Assigned: 2025-07-29
- Published: 2025-07-29
Exploitability & Real-World Risk
The exploitability of this vulnerability is quite high. Attackers can easily craft malicious memos and distribute them through various channels within the Memos platform. The real-world risk is significant. Even though it might seem minor, knowing a user's IP address and User-Agent can be used for tracking, profiling, and even targeted phishing attacks. Imagine this used against activists, journalists, or anyone needing anonymity.
Recommendations
- Update Memos: Upgrade to the latest version of Memos, which contains a fix for this vulnerability.
- Be cautious of memos from untrusted sources: Exercise caution when viewing memos from unknown or untrusted users.
- Monitor network traffic: Consider using network monitoring tools to detect unusual outbound connections from your Memos instance.
Technical Insight
The issue stems from Memos rendering Markdown images without proper sanitization or user consent. When a memo containing a Markdown image is rendered, the application blindly fetches the image from the specified URL. Attackers exploit this by pointing the image URL to a server they control. When a user views the memo, their browser automatically sends a request to the attacker's server, revealing their IP address and User-Agent.
Credit to Researcher(s)
Credit for discovering this vulnerability goes to the researcher(s) who reported it via the GitHub issue tracker.
References
Tags
#CVE-2025-50738 #Memos #InformationDisclosure #Markdown #Security #Privacy
Summary: Memos application (up to v0.24.3) is vulnerable to information disclosure. Embedding a Markdown image with a malicious URL allows attackers to track users by capturing their IP address and User-Agent when the memo is viewed.
CVE ID: CVE-2025-50738
Risk Analysis: Successful exploitation allows attackers to track users, profile them, and potentially launch targeted phishing attacks. This is especially concerning for individuals who require anonymity.
Recommendation: Upgrade to the latest version of Memos and exercise caution when viewing memos from untrusted sources. Consider network monitoring to detect unusual outbound connections.
Timeline
- 2025-07-29: CVE ID Assigned and Published