{"id":"CVE-2026-39853","summary":"osslsigncode has a Stack Buffer Overflow via Unbounded Digest Copy During Signature Verification","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.","aliases":["GHSA-hx87-8754-xvh4"],"modified":"2026-07-08T08:13:05.875142Z","published":"2026-04-09T15:50:26.548Z","database_specific":{"cwe_ids":["CWE-121","CWE-787"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39853.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/mtrojnar/osslsigncode/releases/tag/2.12"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39853.json"},{"type":"ADVISORY","url":"https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-hx87-8754-xvh4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39853"},{"type":"FIX","url":"https://github.com/mtrojnar/osslsigncode/commit/cbee1e723c5a8547302bd841ad9943ed8144db68"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mtrojnar/osslsigncode","events":[{"introduced":"0"},{"fixed":"fac81646228a4d58aa9df41ac2b84c5a21d9d2d9"},{"fixed":"cbee1e723c5a8547302bd841ad9943ed8144db68"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"2.12"}],"cpe":"cpe:2.3:a:osslsigncode_project:osslsigncode:*:*:*:*:*:*:*:*","source":["CPE_RANGE","REFERENCES"]}}],"versions":["2.11","2.10","2.9","2.8","2.7","2.6","2.5","2.4","2.3","2.2","2.1","2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/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"}]}