CVE-2026-39856: CWE-125: Out-of-bounds Read in mtrojnar osslsigncode
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.
AI Analysis
Technical Summary
osslsigncode versions before 2.13 contain an out-of-bounds read vulnerability (CWE-125) in the PE page-hash computation function pe_page_hash_calc(). The function uses PointerToRawData and SizeOfRawData from PE section headers without validating that these point within the mapped file boundaries. An attacker can craft a PE file with section headers referencing data beyond the file end, causing osslsigncode to read invalid memory during page hash computation. This can lead to process crashes when signing with the -ph option or verifying signed files with page hashes. The vulnerability has a CVSS 3.1 score of 5.5 (medium severity) and is fixed in osslsigncode version 2.13.
Potential Impact
The vulnerability can cause osslsigncode to crash due to out-of-bounds memory reads when processing specially crafted PE files. There is no indication of confidentiality or integrity impact, only availability impact (denial of service). No known exploits are reported in the wild.
Mitigation Recommendations
Upgrade osslsigncode to version 2.13 or later, where this vulnerability is fixed. Since no official patch links or vendor advisories are provided, verify the version before use. Avoid processing untrusted PE files with page hashing enabled until upgraded. Patch status is not explicitly confirmed beyond the fixed version mention; check the vendor or project repository for official release notes and updates.
CVE-2026-39856: CWE-125: Out-of-bounds Read in mtrojnar osslsigncode
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
osslsigncode versions before 2.13 contain an out-of-bounds read vulnerability (CWE-125) in the PE page-hash computation function pe_page_hash_calc(). The function uses PointerToRawData and SizeOfRawData from PE section headers without validating that these point within the mapped file boundaries. An attacker can craft a PE file with section headers referencing data beyond the file end, causing osslsigncode to read invalid memory during page hash computation. This can lead to process crashes when signing with the -ph option or verifying signed files with page hashes. The vulnerability has a CVSS 3.1 score of 5.5 (medium severity) and is fixed in osslsigncode version 2.13.
Potential Impact
The vulnerability can cause osslsigncode to crash due to out-of-bounds memory reads when processing specially crafted PE files. There is no indication of confidentiality or integrity impact, only availability impact (denial of service). No known exploits are reported in the wild.
Mitigation Recommendations
Upgrade osslsigncode to version 2.13 or later, where this vulnerability is fixed. Since no official patch links or vendor advisories are provided, verify the version before use. Avoid processing untrusted PE files with page hashing enabled until upgraded. Patch status is not explicitly confirmed beyond the fixed version mention; check the vendor or project repository for official release notes and updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-07T19:13:20.378Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d7d5661cc7ad14daeeafb7
Added to database: 4/9/2026, 4:35:50 PM
Last enriched: 4/9/2026, 4:51:12 PM
Last updated: 4/10/2026, 8:16:43 AM
Views: 8
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