{"id":"CVE-2026-12866","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-12866","generatedAt":"2026-10-28T05:26:13.854Z","title":"All versions of the package expr-eval are vulnerable to Code Execution via the toJSFunction() API.","description":"All versions of the package expr-eval are vulnerable to Code Execution via the toJSFunction() API. An attacker can execute arbitrary JavaScript by supplying crafted expressions that are compiled into native code using new Function(). Because user-controlled expressions are transformed directly into executable JavaScript, attackers can escape the intended expression sandbox and run arbitrary code within the application's context.","published":"2026-06-23T05:17:03.000Z","lastModified":"2026-07-07T19:16:51.000Z","status":"Deferred","sourceIdentifier":"report@snyk.io","cvss":{"version":"4.0","score":9.2,"severity":"CRITICAL","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-94"],"affected":[],"epss":{"score":0.00866,"percentile":0.585,"date":"2026-10-27","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 (0.87%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/silentmatt/expr-eval/blob/master/src/expression.js%23L55","source":"report@snyk.io"},{"url":"https://github.com/silentmatt/expr-eval/issues/292","source":"report@snyk.io"},{"url":"https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-17662018","source":"report@snyk.io"},{"url":"https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690","source":"report@snyk.io"},{"url":"https://security.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-12866","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."}