CVE-2026-39856
5.5 · MEDIUMOverview
CVE-2026-39856 is a medium-severity vulnerability affecting osslsigncode_project osslsigncode. It was published on April 9, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical 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
Remediation
Check the references section for vendor advisories and patches from osslsigncode_project. Update osslsigncode to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| osslsigncode_project | osslsigncode | >= 0, < 2.13 | Affected |
Frequently Asked Questions
What is CVE-2026-39856?
CVE-2026-39856 is a medium-severity vulnerability affecting osslsigncode_project osslsigncode. It was published on April 9, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2026-39856?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-39856?
Check the references section for vendor advisories and patches from osslsigncode_project. Update osslsigncode to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-39856?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-39856 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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