WordPress Core is vulnerable to Stored Cross-Site Scripting via user display names in the Avatar block in various versions up to 6.5.2 due to insufficient output escaping on the display name. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. In addition, it also makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that have the comment block present and display the comment authors avatar.
Weakness
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as “<”, “>”, and “&” that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Wordpress |
Ubuntu |
mantic |
* |
| Wordpress |
Ubuntu |
upstream |
* |
Potential Mitigations
- Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
- The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.
References