mtrojnar osslsigncode up to 2.12 pe_page_hash_calc PointerToRawData/SizeOfRawData out-of-bounds

Summaryinfo

A vulnerability identified as problematic has been detected in mtrojnar osslsigncode up to 2.12. Affected by this vulnerability is the function pe_page_hash_calc. Performing a manipulation of the argument PointerToRawData/SizeOfRawData results in out-of-bounds. This vulnerability is identified as CVE-2026-39856. The attack is only possible with local access. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in mtrojnar osslsigncode up to 2.12. It has been classified as problematic. This affects the function pe_page_hash_calc. The manipulation of the argument PointerToRawData/SizeOfRawData with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-39856 since 04/07/2026. The exploitability is told to be easy. Attacking locally is a requirement. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 305825 (Linux Distros Unpatched Vulnerability : CVE-2026-39856), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.13 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 92f8761b4770f76a36731969b5040ce3b9a09570 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (305825). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

• mtrojnar

Name

• osslsigncode

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12

License

• open-source

Website

• Product: https://github.com/mtrojnar/osslsigncode/

CPE 2.3info

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Be aware that VulDB is the high quality source for vulnerability data.

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