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CVE-2026-39856

MEDIUM CVSS 3.1: 5.5 EPSS 0.02%
Updated Apr 17, 2026
Osslsigncode_Project
Parameter Value
CVSS 5.5 (MEDIUM)
Affected Versions before 2.13
Fixed In 2.13
Type CWE-125 (Out-of-bounds Read)
Vendor Osslsigncode_Project
Public PoC No

osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.13, an out-of-bounds read vulnerability exists in osslsigncode version 2.12 and earlier in the PE page-hash computation code (pe_page_hash_calc()). When processing PE sections for page hashing, the function uses PointerToRawData and SizeOfRawData values from section headers without validating that the referenced region lies within the mapped file.

An attacker can craft a PE file with section headers that point beyond the end of the file. When osslsigncode computes page hashes for such a file, it may attempt to hash data from an invalid memory region, causing an out-of-bounds read and potentially crashing the process. The vulnerability can be triggered while signing a malicious PE file with page hashing enabled (-ph), or while verifying a malicious signed PE file that already contains page hashes.

Verification of an already signed file does not require the verifier to pass -ph. This vulnerability is fixed in 2.13.

Attack Parameters

Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Weakness Type (CWE)

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Osslsigncode_Project Osslsigncode
cpe:2.3:a:osslsigncode_project:osslsigncode:*:*:*:*:*:*:*:*
2.13