{"id":"CVE-2025-66034","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-66034","generatedAt":"2026-10-28T01:50:23.484Z","title":"In versions from 4.33.0 to before 4.60.2, the fonttools varLib (or python3 -m fontTools.varLib) script has an arbitrary file write vulnerability that leads to remote code execution when a malicious .designspace file is processed.","description":"fontTools is a library for manipulating fonts, written in Python. In versions from 4.33.0 to before 4.60.2, the fonttools varLib (or python3 -m fontTools.varLib) script has an arbitrary file write vulnerability that leads to remote code execution when a malicious .designspace file is processed. The vulnerability affects the main() code path of fontTools.varLib, used by the fonttools varLib CLI and any code that invokes fontTools.varLib.main(). This issue has been patched in version 4.60.2.","published":"2025-11-29T01:16:03.000Z","lastModified":"2026-10-18T18:10:00.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-91"],"affected":["fonttools/fonttools"],"epss":{"score":0.00547,"percentile":0.45607,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.55%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv","tags":["Exploit","Vendor Advisory"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-66034","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}