Description
Cross-site scripting (XSS) vulnerability in the ProcessRequest function in mcs/class/System.Web/System.Web/HttpForbiddenHandler.cs in Mono 2.10.8 and earlier allows remote attackers to inject arbitrary web script or HTML via a file with a crafted name and a forbidden extension, which is not properly handled in an error message.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | mono | 2.10.8.1-5 | — |
| Debian 13 | mono | 2.10.8.1-5 | — |
| Debian 12 | mono | 2.10.8.1-5 | — |
| Debian 6.0 | mono | 2.6.7-5.1 | DSA-2512-1 |
Advisories 1
- DSA-2512-1 mono - missing input sanitising Debian Security (DSA / DLA) · Mar 9, 2026