{"id":"UBUNTU-CVE-2026-0819","details":"A stack buffer overflow vulnerability exists in wolfSSL's PKCS7 SignedData encoding functionality. In wc_PKCS7_BuildSignedAttributes(), when adding custom signed attributes, the code passes an incorrect capacity value (esd-\u003esignedAttribsCount) to EncodeAttributes() instead of the remaining available space in the fixed-size signedAttribs[7] array. When an application sets pkcs7-\u003esignedAttribsSz to a value greater than MAX_SIGNED_ATTRIBS_SZ (default 7) minus the number of default attributes already added, EncodeAttributes() writes beyond the array bounds, causing stack memory corruption. In WOLFSSL_SMALL_STACK builds, this becomes heap corruption. Exploitation requires an application that allows untrusted input to control the signedAttribs array size when calling wc_PKCS7_EncodeSignedData() or related signing functions.","modified":"2026-05-20T16:24:06.119729876Z","published":"2026-03-19T17:16:00Z","upstream":["CVE-2026-0819"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-0819"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-0819"},{"type":"REPORT","url":"https://github.com/wolfSSL/wolfssl/pull/9630"}],"affected":[{"package":{"name":"wolfssl","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.4.8+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.4.8+dfsg-1","binary_name":"libcyassl5"},{"binary_name":"libwolfssl0","binary_version":"3.4.8+dfsg-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}},{"package":{"name":"wolfssl","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10.2+dfsg-2","3.12.0+dfsg-1","3.12.2+dfsg-1","3.13.0+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_name":"libwolfssl15","binary_version":"3.13.0+dfsg-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}},{"package":{"name":"wolfssl","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg-2","4.2.0+dfsg-1","4.2.0+dfsg-2","4.2.0+dfsg-3","4.3.0+dfsg-2"],"ecosystem_specific":{"binaries":[{"binary_version":"4.3.0+dfsg-2","binary_name":"libwolfssl24"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}},{"package":{"name":"wolfssl","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.6.0-3","5.0.0-1","5.1.1-1","5.2.0-1","5.2.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libwolfssl32","binary_version":"5.2.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}},{"package":{"name":"wolfssl","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.5.4-2","5.5.4-2.1","5.6.4-2","5.6.6-1.2","5.6.6-1.3","5.6.6-1.3build1"],"ecosystem_specific":{"binaries":[{"binary_version":"5.6.6-1.3build1","binary_name":"libwolfssl42t64"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}},{"package":{"name":"wolfssl","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.7.2-0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libwolfssl42t64","binary_version":"5.7.2-0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}},{"package":{"name":"wolfssl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/wolfssl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.7.2-0.1","5.8.2-1.2","5.8.4-1","5.9.1-0.1"],"ecosystem_specific":{"binaries":[{"binary_version":"5.9.1-0.1","binary_name":"libwolfssl44"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-0819.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:U"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}