CVE-2026-39853

Published: Apr 09, 2026 Last Modified: Apr 13, 2026
ExploitDB:
Other exploit source:
Google Dorks:
HIGH 7,8
Source: [email protected]
Attack Vector: local
Attack Complexity: low
Privileges Required: none
User Interaction: required
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: high

Description

AI Translation Available

osslsigncode is a tool that implements Authenticode signing and timestamping. Prior to 2.12, A stack buffer overflow vulnerability exists in osslsigncode in several signature verification paths. During verification of a PKCS#7 signature, the code copies the digest value from a parsed SpcIndirectDataContent structure into a fixed-size stack buffer (mdbuf[EVP_MAX_MD_SIZE], 64 bytes) without validating that the source length fits within the destination buffer. This pattern is present in the verification handlers for PE, MSI, CAB, and script files. An attacker can craft a malicious signed file with an oversized digest field in SpcIndirectDataContent. When a user verifies such a file with osslsigncode verify, the unbounded memcpy can overflow the stack buffer and corrupt adjacent stack state. This vulnerability is fixed in 2.12.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0001
Percentile
0,0th
Updated

EPSS Score Trend (Last 7 Days)

121

Stack-based Buffer Overflow

Draft
Abstraction: Variant Structure: Simple
Common Consequences
Security Scopes Affected:
Availability Integrity Confidentiality Access Control Other
Potential Impacts:
Modify Memory Dos: Crash, Exit, Or Restart Dos: Resource Consumption (Cpu) Dos: Resource Consumption (Memory) Execute Unauthorized Code Or Commands Bypass Protection Mechanism Other
Applicable Platforms
Languages: C, C++, Memory-Unsafe
Likelihood of Exploit: High
View CWE Details
787

Out-of-bounds Write

Draft
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Availability Other
Potential Impacts:
Modify Memory Execute Unauthorized Code Or Commands Dos: Crash, Exit, Or Restart Unexpected State
Applicable Platforms
Languages: Assembly, C, C++, Memory-Unsafe
Technologies: ICS/OT
Likelihood of Exploit: High
View CWE Details
https://github.com/mtrojnar/osslsigncode/commit/cbee1e723c5…
https://github.com/mtrojnar/osslsigncode/commit/cbee1e723c5a8547302bd841ad9943e…
https://github.com/mtrojnar/osslsigncode/releases/tag/2.12
https://github.com/mtrojnar/osslsigncode/releases/tag/2.12
https://github.com/mtrojnar/osslsigncode/security/advisorie…
https://github.com/mtrojnar/osslsigncode/security/advisories/GHSA-hx87-8754-xvh4