{"id":"UBUNTU-CVE-2026-39853","details":"osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.12, A stack buffer overflow vulnerability exists in osslsigncode in several signature verification paths. During verification of a PKCS#7 signature, the code copies the digest value from a parsed SpcIndirectDataContent structure into a fixed-size stack buffer (mdbuf[EVP_MAX_MD_SIZE], 64 bytes) without validating that the source length fits within the destination buffer. This pattern is present in the verification handlers for PE, MSI, CAB, and script files. An attacker can craft a malicious signed file with an oversized digest field in SpcIndirectDataContent. When a user verifies such a file with osslsigncode verify, the unbounded memcpy can overflow the stack buffer and corrupt adjacent stack state. This vulnerability is fixed in 2.12.","modified":"2026-04-16T09:13:14Z","published":"2026-04-09T16:16:00Z","upstream":["CVE-2026-39853"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-39853"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-39853"},{"type":"REPORT","url":"https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-hx87-8754-xvh4"},{"type":"REPORT","url":"https://github.com/mtrojnar/osslsigncode/commit/cbee1e723c5a8547302bd841ad9943ed8144db68"},{"type":"REPORT","url":"https://github.com/mtrojnar/osslsigncode/releases/tag/2.12"}],"affected":[{"package":{"name":"osslsigncode","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/osslsigncode@1.7.1-1?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"osslsigncode","binary_version":"1.7.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39853.json"}},{"package":{"name":"osslsigncode","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/osslsigncode@1.7.1-3?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.1-2build1","1.7.1-2ubuntu1","1.7.1-3"],"ecosystem_specific":{"binaries":[{"binary_name":"osslsigncode","binary_version":"1.7.1-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39853.json"}},{"package":{"name":"osslsigncode","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/osslsigncode@2.0-1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"osslsigncode","binary_version":"2.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39853.json"}},{"package":{"name":"osslsigncode","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/osslsigncode@2.2-1ubuntu1?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.1-1","2.2-1ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"osslsigncode","binary_version":"2.2-1ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39853.json"}},{"package":{"name":"osslsigncode","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/osslsigncode@2.8-2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5-4","2.8-2"],"ecosystem_specific":{"binaries":[{"binary_name":"osslsigncode","binary_version":"2.8-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39853.json"}},{"package":{"name":"osslsigncode","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/osslsigncode@2.9-2?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9-2"],"ecosystem_specific":{"binaries":[{"binary_name":"osslsigncode","binary_version":"2.9-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-39853.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}