{"id":"CVE-2019-18840","aliases":["DEBIAN-CVE-2019-18840","EUVD-2019-8541","GHSA-42mp-7xj4-8whx","UBUNTU-CVE-2019-18840"],"status":"published","title":"In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing...","description":"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.","severity":{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AC:L/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.01972,"percentile":0.8057,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-787"],"published":"2019-11-09T12:58:52Z","modified":"2026-10-20T10:50:50Z","fixes":[{"ecosystem":"Debian:12","package":"wolfssl","fixed_in":["4.2.0+dfsg-3"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"wolfssl","fixed_in":["4.2.0+dfsg-3"],"sources":["osv"]},{"ecosystem":"Ubuntu:20.04:LTS","package":"wolfssl","fixed_in":["4.2.0+dfsg-3"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.0+dfsg-3"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.2.0+dfsg-3"}]}]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"wolfssl","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"]}],"products":[{"vendor":"wolfssl","product":"wolfssl"}],"references":[{"url":"https://github.com/wolfSSL/wolfssl/issues/2555","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2019-18840"},{"url":"https://github.com/advisories/GHSA-42mp-7xj4-8whx"},{"url":"https://security-tracker.debian.org/tracker/CVE-2019-18840","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2019-18840","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2019-18840","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2019-18840","description":"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.","status":"published","published":"2019-11-09T12:58:52Z","modified":"2024-08-05T02:02:39.61Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AC:L/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N","level":"high","assessor":"cna"}],"updated_at":"2026-11-02T14:32:23.803059Z"}],"euvd":[{"id":"EUVD-2019-8541","description":"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.","status":"published","published":"2019-11-09T12:58:52Z","modified":"2024-08-05T02:02:39Z","cvss":[{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AC:L/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N","level":"high"}],"updated_at":"2026-11-03T02:40:27.303586Z"}],"ghsa":[{"id":"GHSA-42mp-7xj4-8whx","title":"In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing...","description":"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.","status":"published","published":"2022-05-24T22:01:06Z","modified":"2023-01-30T05:05:10Z","updated_at":"2026-11-02T14:47:12.945495Z"}],"nvd":[{"id":"CVE-2019-18840","description":"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.","status":"published","published":"2019-11-09T13:15:10.227Z","modified":"2026-06-17T02:25:26.82Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"},{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:05:35.052973Z"}],"osv":[{"id":"CVE-2019-18840","description":"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.","status":"published","published":"2019-11-09T13:15:10.227Z","modified":"2026-10-20T10:50:50.657012475Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:44:11.673963Z"},{"id":"DEBIAN-CVE-2019-18840","description":"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.","status":"published","published":"2019-11-09T13:15:10.227Z","modified":"2026-09-21T07:01:54.421583154Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:31.867036Z"},{"id":"UBUNTU-CVE-2019-18840","description":"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.","status":"published","published":"2019-11-09T13:15:00Z","modified":"2026-04-22T12:14:39.369581Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"},{"version":"3.0","score":7.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:54:20.325378Z"}]}}