CVE-2002-0534 in Postboard
Summary
by MITRE
PostBoard 2.0.1 and earlier with BBcode allows remote attackers to cause a denial of service (CPU consumption) and corrupt the database via null \0 characters within [code] tags.
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Analysis
by VulDB Data Team • 09/16/2025
The vulnerability identified as CVE-2002-0534 affects PostBoard 2.0.1 and earlier versions that support BBcode formatting. This represents a critical security flaw that manifests through improper input validation within the BBcode parsing mechanism. The vulnerability specifically targets the [code] tag processing functionality, where the application fails to adequately sanitize input containing null characters, creating a condition that can be exploited by remote attackers to disrupt system operations.
The technical implementation of this vulnerability stems from the application's insufficient handling of null byte characters within BBcode [code] tags. When a malicious user submits content containing null characters within these tags, the parsing routine becomes susceptible to malformed input processing that consumes excessive CPU resources. This condition creates a resource exhaustion scenario where the application's processing capacity becomes overwhelmed, leading to denial of service conditions. The vulnerability is classified under CWE-129 as an insufficient input validation issue, specifically related to improper validation of input data within code execution contexts.
The operational impact of this vulnerability extends beyond simple service disruption to include potential database corruption. The null character injection within code tags can cause the application's database management system to process malformed data structures, leading to data integrity issues. This dual impact of CPU consumption and database corruption makes the vulnerability particularly dangerous for systems relying on PostBoard for content management. The attack vector requires only remote access to the application's input processing functionality, making it easily exploitable by attackers with minimal privileges.
The exploitation of this vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries leverage application flaws to consume system resources. The vulnerability demonstrates poor input sanitization practices that violate security best practices outlined in OWASP Top Ten and other industry standards. Organizations using affected PostBoard versions face significant risk of operational disruption and data integrity compromise, particularly in environments where continuous availability is critical.
Mitigation strategies should focus on immediate input validation and sanitization of all BBcode content, particularly within [code] tags. Implementing proper null character filtering and input length restrictions can prevent exploitation of this vulnerability. System administrators should upgrade to PostBoard versions that address this specific flaw, as the vulnerability has been resolved in subsequent releases. Additionally, implementing web application firewalls with content filtering capabilities can provide additional protection layers against similar injection attacks targeting code parsing functionalities.