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 a CWE-125 out-of-bounds read vulnerability in the PE page-hash computation function pe_page_hash_calc(). The function does not validate that the PointerToRawData and SizeOfRawData fields in PE section headers point to valid regions within the mapped file. An attacker can craft a PE file with section headers referencing data beyond the file's end, causing osslsigncode to read invalid memory during page hash computation. This can trigger a process crash during signing with the -ph option or during verification of a signed file containing 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 maliciously crafted PE files. There is no indication of confidentiality or integrity impact, only availability impact (denial of service). No known exploits in the wild have been reported.
Mitigation Recommendations
Upgrade osslsigncode to version 2.13 or later, where this vulnerability is fixed. Since no official patch link or advisory is provided, users should verify the version before use. Patch status is not explicitly confirmed beyond the fix in version 2.13. No other mitigation is indicated.
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 a CWE-125 out-of-bounds read vulnerability in the PE page-hash computation function pe_page_hash_calc(). The function does not validate that the PointerToRawData and SizeOfRawData fields in PE section headers point to valid regions within the mapped file. An attacker can craft a PE file with section headers referencing data beyond the file's end, causing osslsigncode to read invalid memory during page hash computation. This can trigger a process crash during signing with the -ph option or during verification of a signed file containing 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 maliciously crafted PE files. There is no indication of confidentiality or integrity impact, only availability impact (denial of service). No known exploits in the wild have been reported.
Mitigation Recommendations
Upgrade osslsigncode to version 2.13 or later, where this vulnerability is fixed. Since no official patch link or advisory is provided, users should verify the version before use. Patch status is not explicitly confirmed beyond the fix in version 2.13. No other mitigation is indicated.
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: 4/17/2026, 11:54:19 AM
Last updated: 5/25/2026, 12:22:40 PM
Views: 58
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