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CVE-2026-39853

osslsigncode has a Stack Buffer Overflow via Unbounded Digest Copy During Signature Verification PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
mtrojnar / osslsigncodeaffected < 2.12

CWE

CWE-121, CWE-787

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.