CVE-2026-39856
osslsigncode has an Out-of-Bounds Read via Unvalidated Section Bounds in PE Page Hash Calculation
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.
INFO
Published Date :
April 9, 2026, 5:16 p.m.
Last Modified :
Oct. 26, 2026, 10:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-39856
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update osslsigncode to version 2.13 or later.
- Verify signed PE files.
- Ensure PE files are not maliciously crafted.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-39856.
| URL | Resource |
|---|---|
| https://github.com/mtrojnar/osslsigncode/commit/92f8761b4770f76a36731969b5040ce3b9a09570 | Patch |
| https://github.com/mtrojnar/osslsigncode/releases/tag/2.13 | Product Release Notes |
| https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-rjrx-chvw-8jw8 | Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-39856 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-39856
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-39856 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-39856 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: osslsigncode de mtrojnar, Description: osslsigncode es una herramienta que implementa la firma y el sellado de tiempo Authenticode. Antes de la versión 2.13, existe una vulnerabilidad de lectura fuera de límites en osslsigncode versión 2.12 y anteriores en el código de cálculo de hash de página PE (pe_page_hash_calc()). Al procesar secciones PE para el hashing de páginas, la función utiliza los valores PointerToRawData y SizeOfRawData de los encabezados de sección sin validar que la región referenciada se encuentre dentro del archivo mapeado. Un atacante puede crear un archivo PE con encabezados de sección que apuntan más allá del final del archivo. Cuando osslsigncode calcula los hashes de página para dicho archivo, puede intentar hacer hash de datos de una región de memoria no válida, causando una lectura fuera de límites y potencialmente bloqueando el proceso. La vulnerabilidad puede activarse al firmar un archivo PE malicioso con el hashing de páginas habilitado (-ph), o al verificar un archivo PE firmado malicioso que ya contiene hashes de página. La verificación de un archivo ya firmado no requiere que el verificador pase -ph. Esta vulnerabilidad está corregida en la versión 2.13. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'mtrojnar', 'product': 'osslsigncode', 'versions': [{'status': 'affected', 'version': '< 2.13'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-39856', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-04-13T20:06:24.980414Z'} -
Initial Analysis by [email protected]
Apr. 17, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:osslsigncode_project:osslsigncode:*:*:*:*:*:*:*:* versions up to (excluding) 2.13 Added Reference Type GitHub, Inc.: https://github.com/mtrojnar/osslsigncode/commit/92f8761b4770f76a36731969b5040ce3b9a09570 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/mtrojnar/osslsigncode/releases/tag/2.13 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-rjrx-chvw-8jw8 Types: Patch, Vendor Advisory -
New CVE Received by [email protected]
Apr. 09, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Added CWE CWE-125 Added Reference https://github.com/mtrojnar/osslsigncode/commit/92f8761b4770f76a36731969b5040ce3b9a09570 Added Reference https://github.com/mtrojnar/osslsigncode/releases/tag/2.13 Added Reference https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-rjrx-chvw-8jw8