{"cve":"CVE-2023-52081","nvd":{"published":"2023-12-28T16:16:02.090","modified":"2026-06-17T06:42:02.147","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-74","CWE-176"],"references":["https://github.com/ewen-lbh/ffcss/commit/f9c491874b858a32fcae15045f169fd7d02f90dc","https://github.com/ewen-lbh/ffcss/security/advisories/GHSA-wpmx-564x-h2mh","https://github.com/ewen-lbh/ffcss/commit/f9c491874b858a32fcae15045f169fd7d02f90dc","https://github.com/ewen-lbh/ffcss/security/advisories/GHSA-wpmx-564x-h2mh"],"products":["ewen-lbh:firefox_css"],"source":"nvd","synced_at":"2026-10-19T21:43:38.875533635+00:00"},"epss":{"cve":"CVE-2023-52081","score":0.00522,"percentile":0.44344,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-wpmx-564x-h2mh","url":"https://osv.dev/vulnerability/GHSA-wpmx-564x-h2mh","summary":"ewen-lbh/ffcss Late-Unicode normalization vulnerability","modified":"2026-09-10T03:50:09.240545301Z","packages":[{"ecosystem":"Go","name":"github.com/ewen-lbh/ffcss","purl":"pkg:golang/github.com/ewen-lbh/ffcss","ranges":["<0.2.0"],"fixed":["0.2.0"]}]},{"id":"GO-2023-2426","url":"https://osv.dev/vulnerability/GO-2023-2426","summary":"ewen-lbh/ffcss Late-Unicode normalization vulnerability in github.com/ewen-lbh/ffcss","modified":"2026-03-03T04:54:25.823743Z","packages":[{"ecosystem":"Go","name":"github.com/ewen-lbh/ffcss","purl":"pkg:golang/github.com/ewen-lbh/ffcss","ranges":["<0.2.0"],"fixed":["0.2.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}