CVE-2026-39855
April 9, 2026, 5:16 p.m.
5.5
Medium
Description
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.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Osslsigncode |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-125
Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | osslsigncode | osslsigncode | <2.13 | / | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: LOCAL
- Attack Complexity: LOW
- Privileges Required: NONE
- Scope: UNCHANGED
- Confidentiality Impact: NONE
- Integrity Impact: NONE
- Availability Impact: HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Timeline
Published: April 9, 2026, 5:16 p.m.
Last Modified: April 9, 2026, 5:16 p.m.
Last Modified: April 9, 2026, 5:16 p.m.
Status : Received
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.