CVE-2023-27592 Stored XSS in Miniflux when opening a broken image due to unescaped ServerError in proxy handler
Attackers can execute arbitrary JavaScript in a victim's browser via crafted RSS feeds, potentially leading to account takeover or admin access.
- 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
- Available
What is CVE-2023-27592?
CVE-2023-27592 is a medium-severity cross-site scripting vulnerability in miniflux v2, published on 17 Mar 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Miniflux is a feed reader. Since v2.0.25, Miniflux will automatically proxy images served over HTTP to prevent mixed content errors.
When an outbound request made by the Go HTTP client fails, the `html.ServerError` is returned unescaped without the expected Content Security Policy header added to valid responses.
By creating an RSS feed item with the inline description containing an `<img>` tag with a `srcset` attribute pointing to an invalid URL like `http:a<script>alert(1)</script>`, we can coerce the proxy handler into an error condition where the invalid URL is returned unescaped and in full.
This results in JavaScript execution on the Miniflux instance as soon as the user is convinced (e.g. by a message in the alt text) to open the broken image.
An attacker can execute arbitrary JavaScript in the context of a victim Miniflux user when they open a broken image in a crafted RSS feed. This can be used to perform actions on the Miniflux instance as that user and gain administrative access to the Miniflux instance if it is reachable and the victim is an administrator.
A patch is available in version 2.0.43. As a workaround sisable image proxy; default value is `http-only`.
Weakness: CWE-79
Which versions are affected by CVE-2023-27592?
2 open source packages ship an affected version, including miniflux.app/v2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
miniflux.app/v2 Go | From 2.0.25 | 2.0.43 |
miniflux.app/v2 Go | From 2.0.25 | 2.0.43 |
Products include Miniflux Project Miniflux.
How do I fix CVE-2023-27592?
Upgrade miniflux.app/v2 to 2.0.43 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2023-27592 being exploited?
There is no known exploitation of CVE-2023-27592 in the wild and no public exploit code.
Other vulnerabilities in miniflux v2
Sources
Also known as GHSA-mqqg-xjhj-wfgw.