EUVD-2026-20946

| CVE-2026-39856 MEDIUM
2026-04-09 GitHub_M
5.5
CVSS 3.1
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CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

3
EUVD ID Assigned
Apr 09, 2026 - 16:30 euvd
EUVD-2026-20946
Analysis Generated
Apr 09, 2026 - 16:30 vuln.today
CVE Published
Apr 09, 2026 - 16:03 nvd
MEDIUM 5.5

Description

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.

Analysis

Out-of-bounds read in osslsigncode versions 2.12 and earlier allows local attackers to crash the application via crafted PE files with malicious section headers during page-hash computation. The vulnerability exists in the pe_page_hash_calc() function, which fails to validate that section headers' PointerToRawData and SizeOfRawData values reference valid file regions. …

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Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: +0.0
CVSS: +28
POC: 0

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EUVD-2026-20946 vulnerability details – vuln.today

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