CVE-2026-39855 (GCVE-0-2026-39855)

Vulnerability from cvelistv5 – Published: 2026-04-09 15:58 – Updated: 2026-04-09 19:22
VLAI?
Title
osslsigncode has an Integer Underflow in PE Page Hash Calculation Can Cause Out-of-Bounds Read
Summary
osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.13, an integer underflow vulnerability exists in osslsigncode version 2.12 and earlier in the PE page-hash computation code (pe_page_hash_calc()). When page hash processing is performed on a PE file, the function subtracts hdrsize from pagesize without first validating that pagesize >= hdrsize. If a malicious PE file sets SizeOfHeaders (hdrsize) larger than SectionAlignment (pagesize), the subtraction underflows and produces a very large unsigned length. The code allocates a zero-filled buffer of pagesize bytes and then attempts to hash pagesize - hdrsize bytes from that buffer. After the underflow, this results in an out-of-bounds read from the heap and can crash 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.
CWE
  • CWE-125 - Out-of-bounds Read
  • CWE-190 - Integer Overflow or Wraparound
  • CWE-191 - Integer Underflow (Wrap or Wraparound)
Assigner
Impacted products
Vendor Product Version
mtrojnar osslsigncode Affected: < 2.13
Create a notification for this product.
Show details on NVD website

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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