{"id":"UBUNTU-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":"2025-09-08T16:45:40Z","published":"2019-11-09T13:15:00Z","upstream":["CVE-2019-18840"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2019-18840"},{"type":"REPORT","url":"https://github.com/wolfSSL/wolfssl/issues/2555"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2019-18840"}],"affected":[{"package":{"name":"wolfssl","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/wolfssl@4.2.0+dfsg-3?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.0+dfsg-3"}]}],"versions":["4.1.0+dfsg-2","4.2.0+dfsg-1","4.2.0+dfsg-2"],"ecosystem_specific":{"binaries":[{"binary_version":"4.2.0+dfsg-3","binary_name":"libwolfssl-dev"},{"binary_version":"4.2.0+dfsg-3","binary_name":"libwolfssl23"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2019/UBUNTU-CVE-2019-18840.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}