{"id":"CVE-2023-23557","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-23557","generatedAt":"2026-10-27T20:54:13.044Z","title":"An error in Hermes' algorithm for copying objects properties prior to commit a00d237346894c6067a594983be6634f4168c9ad could be used by a malicious attacker to execute arbitrary code via type confusion.","description":"An error in Hermes' algorithm for copying objects properties prior to commit a00d237346894c6067a594983be6634f4168c9ad could be used by a malicious attacker to execute arbitrary code via type confusion. Note that this is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.","published":"2023-05-18T22:15:10.000Z","lastModified":"2026-06-17T05:37:26.000Z","status":"Modified","sourceIdentifier":"cve-assign@fb.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-843"],"affected":["facebook/hermes"],"epss":{"score":0.00891,"percentile":0.59149,"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 (0.89%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/facebook/hermes/commit/a00d237346894c6067a594983be6634f4168c9ad","tags":["Patch","Vendor Advisory"],"source":"cve-assign@fb.com"},{"url":"https://www.facebook.com/security/advisories/cve-2023-23557","tags":["Patch","Vendor Advisory"],"source":"cve-assign@fb.com"},{"url":"https://github.com/facebook/hermes/commit/a00d237346894c6067a594983be6634f4168c9ad","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.facebook.com/security/advisories/cve-2023-23557","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-23557","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."}