CyberSecBulletin
CVE-2024-41659NVD status: Analyzed

memos: Permissive Cross-domain Security Policy with Untrusted Domains

Published Updated By the CyberSecBulletin desk

CVE-2024-41659 is a high-severity permissive cross-domain security policy with untrusted domains vulnerability in memos from Usememos, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected memos versions: < 0.21.0; 0.20.1 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of memos you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Usememosmemos< 0.21.0; 0.20.1 and earlierNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. Scored by CNA (github.com).

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Permissive Cross-domain Security Policy with Untrusted Domains

The product uses a web-client protection mechanism such as a Content Security Policy (CSP) or cross-domain policy file, but the policy includes untrusted domains with which the web client is allowed to communicate.

How developers prevent this class of flaw

  • Define a restrictive Content Security Policy or cross-domain policy file.
  • Avoid using wildcards in the CSP / cross-domain policy file. Any domain matching the wildcard expression will be implicitly trusted, and can perform two-way interaction with the target server.
  • For Flash, modify crossdomain.xml to use meta-policy options such as 'master-only' or 'none' to reduce the possibility of an attacker planting extraneous cross-domain policy files on a server.

More Permissive Cross-domain Security Policy with Untrusted Domains vulnerabilities (CWE-942)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Technical write-ups (may include proof of concept)

Other vulnerabilities in memos

All memos vulnerabilities

Recent Permissive Cross-domain Security Policy with Untrusted Domains vulnerabilities

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