CVE-2021-41101 CORS `Access-Control-Allow-Origin` settings are too lenient
Lenient CORS settings allow attackers to exploit XSS on subdomains to access user cookies and interact with the Wire API.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-41101?
CVE-2021-41101 is a medium-severity vulnerability in wireapp wire-server, published on 30 Sep 2021. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
wire-server is an open-source back end for Wire, a secure collaboration platform. Before version 2.106.0, the CORS ` Access-Control-Allow-Origin ` header set by `nginz` is set for all subdomains of `.wire.com` (including `wire.com`). This means that if somebody were to find an XSS vector in any of the subdomains, they could use it to talk to the Wire API using the user's Cookie. A patch does not exist, but a workaround does. To make sure that a compromise of one subdomain does not yield access to the cookie of another, one may limit the `Access-Control-Allow-Origin` header to apps that actually require the cookie (account-pages, team-settings and the webapp).
Weakness: CWE-79
Which versions are affected by CVE-2021-41101?
It affects 1 product.
Products include Wire Wire Server.
How do I fix CVE-2021-41101?
No fix has been published for CVE-2021-41101 yet. Limit exposure of the affected software until one is available.
Is CVE-2021-41101 being exploited?
There is no known exploitation of CVE-2021-41101 in the wild and no public exploit code.
Other vulnerabilities in wireapp wire-server
Sources
Also known as GHSA-v7xx-cx8m-g66p.