CVE-2025-31136 FreshRSS vulnerable to Cross-site Scripting by <iframe>'ing a vulnerable same-origin page in a feed entry
Attacker-controlled feed entries can execute arbitrary JavaScript via unsanitized SVG favicons, leading to account takeover or server code execution.
- 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-2025-31136?
CVE-2025-31136 is a medium-severity cross-site scripting vulnerability in FreshRSS, published on 4 Jun 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
FreshRSS is a self-hosted RSS feed aggregator. Prior to version 1.26.2, it's possible to run arbitrary JavaScript on the feeds page. This occurs by combining a cross-site scripting (XSS) issue that occurs in `f.php` when SVG favicons are downloaded from an attacker-controlled feed containing `<script>` tags inside of them that aren't sanitized, with the lack of CSP in `f.php` by embedding the malicious favicon in an iframe (that has `sandbox="allow-scripts allow-same-origin"` set as its attribute). An attacker needs to control one of the feeds that the victim is subscribed to, and also must have an account on the FreshRSS instance. Other than that, the iframe payload can be embedded as one of two options. The first payload requires user interaction (the user clicking on the malicious feed entry) with default user configuration, and the second payload fires instantly right after the user adds the feed or logs into the account while the feed entry is still visible. This is because of lazy image loading functionality, which the second payload bypasses. An attacker can gain access to the victim's account by exploiting this vulnerability. If the victim is an admin it would be possible to delete all users (cause damage) or execute arbitrary code on the server by modifying the update URL using fetch() via the XSS. Version 1.26.2 has a patch for the issue.
Weakness: CWE-79
Which versions are affected by CVE-2025-31136?
It affects 1 product.
Products include Freshrss Freshrss.
How do I fix CVE-2025-31136?
No fix has been published for CVE-2025-31136 yet. Limit exposure of the affected software until one is available.
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-2025-31136 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-31136 exists.
Other vulnerabilities in FreshRSS
- CVE-2025-54875 FreshRSS: Unauthorized creation of admin user when registration is enabled
- CVE-2025-54592 FreshRSS has Incomplete Session Termination on Logout
- CVE-2025-62166 FreshRSS has an IDOR which allows for viewing feeds of any user and leaking tokens
- CVE-2025-54591 FreshRSS: Unauthenticated users can view default user's information
- CVE-2025-58173 FreshRSS vulnerable to authenticated RCE via path traversal inside include()
Sources
Also known as GHSA-f6r4-jrvc-cfmr.