{"id":"CVE-2019-18840","details":"In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the domain name location index is mishandled. Because a pointer is overwritten, there is an invalid free.","modified":"2026-04-10T04:16:10.632036Z","published":"2019-11-09T13:15:10.227Z","references":[{"type":"EVIDENCE","url":"https://github.com/wolfSSL/wolfssl/issues/2555"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/wolfssl/wolfssl","events":[{"introduced":"50fbdb961fd8c2d8123064e567ae8ec44167732d"},{"last_affected":"cb7b4af9861ad627faffdc3d24a196c2d11930b8"}],"database_specific":{"versions":[{"introduced":"4.1.0"},{"last_affected":"4.2.0c"}]}}],"versions":["v4.1.0-stable","v4.2.0-stable","v4.2.0c"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-18840.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}