Overview
CVE-2025-40906 is a high-severity vulnerability that affects BSON::XS versions 0.8.4 and earlier for Perl. This vulnerability, which stems from the bundled libbson 1.1.7, puts various systems at risk, potentially leading to system compromise or data leakage. Although BSON::XS has reached its end of life as of August 13, 2020, and is no longer supported, many systems using this distribution may still be at risk. Given the severity of this vulnerability, it is essential to understand the nature of this exploit, the products affected, and how to mitigate its impact.
Vulnerability Summary
CVE ID: CVE-2025-40906
Severity: Critical (CVSS: 9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise or data leakage
Affected Products
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Product | Affected Versions
BSON::XS for Perl | 0.8.4 and earlier
How the Exploit Works
The vulnerability lies in the bundled libbson 1.1.7 in BSON::XS versions 0.8.4 and earlier. An attacker can exploit this vulnerability by sending specially crafted data to an application using the affected BSON::XS distribution. Since libbson does not correctly validate input, this could lead to unexpected behavior, including the execution of arbitrary code, system compromise, and data leakage.
Conceptual Example Code
The following is a conceptual example of how an attacker might exploit this vulnerability:
use BSON::XS;
my $malicious_data = '...'; # specially crafted data that exploits the vulnerability
my $bson = BSON::XS->new;
my $perl_data = $bson->decode($malicious_data);In this conceptual example, an attacker sends malicious data to a Perl application using the vulnerable BSON::XS distribution. The application, in turn, attempts to decode this data, triggering the vulnerability and leading to potential system compromise or data leakage.
Recommendations for Mitigation
Given the severity of this vulnerability, it is crucial to implement mitigation measures immediately. Since BSON::XS has reached its end of life and is no longer supported, applying a vendor patch is not possible. As a temporary mitigation, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used to monitor and filter out potential exploit attempts. Long-term, however, users should consider migrating to a supported BSON implementation.