CVE-2025-31136
FreshRSS Cross-Site Scripting (XSS) Vulnerability
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.
INFO
Published Date :
June 4, 2025, 8:15 p.m.
Last Modified :
June 5, 2025, 8:12 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
5.5
Exploitability Score :
1.2
References to Advisories, Solutions, and Tools
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CVE-2025-31136
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CVE-2025-31136
vulnerability anywhere in the article.
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CVE-2025-31136
vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 04, 2025
Action Type Old Value New Value Added Reference https://github.com/FreshRSS/FreshRSS/security/advisories/GHSA-f6r4-jrvc-cfmr -
New CVE Received by [email protected]
Jun. 04, 2025
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:L Added CWE CWE-79 Added Reference https://github.com/FreshRSS/FreshRSS/commit/426e3054c237c2b98667ebeacbbdb5caa88e7b1f Added Reference https://github.com/FreshRSS/FreshRSS/security/advisories/GHSA-f6r4-jrvc-cfmr
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-31136
is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-31136
weaknesses.