CVE-2026-39856osslsigncode has an Out-of-Bounds Read via Unvalidated Section Bounds in PE Page Hash Calculation

Official 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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-rjrx-chvw-8jw8 x_refsource_CONFIRM
• https://github.com/mtrojnar/osslsigncode/commit/92f8761b4770f76a36731969b5040ce3b9a09570 x_refsource_MISC
• https://github.com/mtrojnar/osslsigncode/releases/tag/2.13 x_refsource_MISC