{"id":"UBUNTU-CVE-2026-40253","details":"openCryptoki is a PKCS#11 library and provides tooling for Linux and AIX. In versions 3.26.0 and below, the BER/DER decoding functions in the shared common library (asn1.c) accept a raw pointer but no buffer length parameter, and trust attacker-controlled BER length fields without validating them against actual buffer boundaries. All primitive decoders are affected: ber_decode_INTEGER, ber_decode_SEQUENCE, ber_decode_OCTET_STRING, ber_decode_BIT_STRING, and ber_decode_CHOICE. Additionally, ber_decode_INTEGER can produce integer underflows when the encoded length is zero. An attacker supplying a malformed BER-encoded cryptographic object through PKCS#11 operations such as C_CreateObject or C_UnwrapKey, token loading from disk, or remote backend communication can trigger out-of-bounds reads. This affects all token backends (Soft, ICA, CCA, TPM, EP11, ICSF) since the vulnerable code is in the shared common library. A patch is available thorugh commit ed378f463ef73364c89feb0fc923f4dc867332a3.","modified":"2026-09-01T21:12:03.610905143Z","published":"2026-04-16T23:16:00Z","related":["USN-8686-1","USN-8707-1"],"upstream":["CVE-2026-40253"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-40253"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-40253"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8686-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8707-1"}],"affected":[{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.1+dfsg-3ubuntu5","3.4.1+dfsg-1ubuntu1","3.4.1+dfsg-1ubuntu2","3.4.1+dfsg-1ubuntu3","3.4.1+dfsg-1ubuntu4","3.4.1+dfsg-1ubuntu4.1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.4.1+dfsg-1ubuntu4.1","binary_name":"libopencryptoki0"},{"binary_version":"3.4.1+dfsg-1ubuntu4.1","binary_name":"opencryptoki"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}},{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.7.0+dfsg-4","3.8.1+dfsg-2","3.8.1+dfsg-3","3.8.2+dfsg-0ubuntu1","3.9.0+dfsg-0ubuntu1","3.9.0+dfsg-0ubuntu1.1","3.9.0+dfsg-0ubuntu1.2","3.9.0+dfsg-0ubuntu1.3","3.9.0+dfsg-0ubuntu1.4"],"ecosystem_specific":{"binaries":[{"binary_name":"libopencryptoki0","binary_version":"3.9.0+dfsg-0ubuntu1.4"},{"binary_version":"3.9.0+dfsg-0ubuntu1.4","binary_name":"opencryptoki"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}},{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.11.1+dfsg-0ubuntu2","3.11.1+dfsg-0ubuntu3","3.12.1+dfsg-0ubuntu1","3.13.0+dfsg-0ubuntu4","3.13.0+dfsg-0ubuntu5","3.13.0+dfsg-0ubuntu5.1","3.13.0+dfsg-0ubuntu5.2"],"ecosystem_specific":{"binaries":[{"binary_name":"libopencryptoki0","binary_version":"3.13.0+dfsg-0ubuntu5.2"},{"binary_version":"3.13.0+dfsg-0ubuntu5.2","binary_name":"opencryptoki"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}},{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.17.0+dfsg+20220202.b40982e-0ubuntu1.3"}]}],"versions":["3.16.0+dfsg-0ubuntu1","3.16.0+dfsg-0ubuntu2","3.16.0+dfsg-0ubuntu3","3.17.0+dfsg+20220202.b40982e-0ubuntu1","3.17.0+dfsg+20220202.b40982e-0ubuntu1.1","3.17.0+dfsg+20220202.b40982e-0ubuntu1.2"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"3.17.0+dfsg+20220202.b40982e-0ubuntu1.3","binary_name":"libopencryptoki0"},{"binary_version":"3.17.0+dfsg+20220202.b40982e-0ubuntu1.3","binary_name":"opencryptoki"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}},{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.23.0+dfsg-0ubuntu3.1"}]}],"versions":["3.21.0+dfsg-0ubuntu1","3.21.0+dfsg-0ubuntu2","3.22.0+dfsg-0ubuntu1","3.23.0+dfsg-0ubuntu1","3.23.0+dfsg-0ubuntu2","3.23.0+dfsg-0ubuntu3"],"ecosystem_specific":{"binaries":[{"binary_name":"libopencryptoki0","binary_version":"3.23.0+dfsg-0ubuntu3.1"},{"binary_version":"3.23.0+dfsg-0ubuntu3.1","binary_name":"opencryptoki"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}},{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.24.0+git20250128.0462717+dfsg-0ubuntu1","3.25.0+dfsg-0ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libopencryptoki0","binary_version":"3.25.0+dfsg-0ubuntu1"},{"binary_version":"3.25.0+dfsg-0ubuntu1","binary_name":"opencryptoki"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}},{"package":{"name":"opencryptoki","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/opencryptoki?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.26.0+dfsg-0ubuntu1.1"}]}],"versions":["3.25.0+dfsg-0ubuntu1","3.26.0+dfsg-0ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libopencryptoki0","binary_version":"3.26.0+dfsg-0ubuntu1.1"},{"binary_name":"opencryptoki","binary_version":"3.26.0+dfsg-0ubuntu1.1"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40253.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}