CVE-2023-52081 ewen-lbh/ffcss late-Unicode normalization vulnerability
Attackers can bypass input validation in ffcss using Unicode normalization to inject restricted characters, potentially affecting theme lookup logic.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-52081?
CVE-2023-52081 is a medium-severity vulnerability in ewen-lbh ffcss, published on 28 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
ffcss is a CLI interface to apply and configure Firefox CSS themes. Prior to 0.2.0, the function `lookupPreprocess()` is meant to apply some transformations to a string by disabling characters in the regex `[-_ .]`. However, due to the use of late Unicode normalization of type NFKD, it is possible to bypass that validation and re-introduce all the characters in the regex `[-_ .]`. The `lookupPreprocess()` can be easily bypassed with equivalent Unicode characters like U+FE4D (﹍), which would result in the omitted U+005F (_), for instance. The `lookupPreprocess()` function is only ever used to search for themes loosely (case insensitively, while ignoring dashes, underscores and dots), so the actual security impact is classified as low. This vulnerability is fixed in 0.2.0. There are no known workarounds.
Which versions are affected by CVE-2023-52081?
3 open source packages ship an affected version, including github.com/ewen-lbh/ffcss. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/ewen-lbh/ffcss Go | All versions | 0.2.0 |
github.com/ewen-lbh/ffcss Go | All versions | 0.2.0 |
github.com/ewen-lbh/ffcss Go | All versions | 0.2.0 |
Products include Ewen-Lbh Firefox Css.
How do I fix CVE-2023-52081?
Upgrade github.com/ewen-lbh/ffcss to 0.2.0 or later.
Is CVE-2023-52081 being exploited?
There is no known exploitation of CVE-2023-52081 in the wild and no public exploit code.
Sources
Also known as GHSA-wpmx-564x-h2mh, GO-2023-2426.