CVE-2022-34033 in HTMLDoc
Summary
by MITRE • 07/19/2022
HTMLDoc v1.9.15 was discovered to contain a heap overflow via (write_header) /htmldoc/htmldoc/html.cxx:273.
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Analysis
by VulDB Data Team • 01/23/2025
The vulnerability identified as CVE-2022-34033 affects HTMLDoc version 1.9.15 and represents a critical heap overflow condition that occurs within the write_header function of the htmldoc/html.cxx source file at line 273. This flaw manifests when the application processes HTML documents and attempts to write header information, creating a scenario where memory allocation operations can be manipulated to exceed buffer boundaries. The heap overflow vulnerability stems from insufficient input validation and boundary checking during the header processing phase, allowing attackers to craft malicious HTML content that triggers the exploitable condition. Such vulnerabilities are particularly dangerous as they can lead to arbitrary code execution or system compromise when the vulnerable application processes untrusted input.
The technical implementation of this heap overflow involves the write_header function failing to properly validate the size of data being written to heap-allocated memory regions. When HTMLDoc encounters certain malformed header structures or excessively long header values, the application allocates insufficient memory buffers to accommodate the incoming data. This memory corruption occurs at the heap level where the application manages dynamic memory allocation for document processing operations. The vulnerability specifically targets the memory management practices within the html.cxx file, where header data is processed without adequate bounds checking, making it susceptible to overflow conditions that can overwrite adjacent memory locations.
From an operational perspective, this vulnerability poses significant risks to systems that utilize HTMLDoc for document conversion or processing tasks. The heap overflow can result in application crashes, denial of service conditions, or more severe consequences including remote code execution depending on the system configuration and memory layout. Attackers can exploit this vulnerability by submitting specially crafted HTML documents that trigger the overflow during header processing, potentially leading to complete system compromise. The impact is particularly concerning in server environments where HTMLDoc is used to process user-uploaded content or web-based documents, as it creates an attack surface that can be leveraged for privilege escalation or persistent access.
Mitigation strategies for CVE-2022-34033 should prioritize immediate patching of HTMLDoc to version 1.9.16 or later, which contains the necessary fixes for the heap overflow condition. Organizations should implement input validation measures to filter or sanitize HTML content before processing, particularly focusing on header data that could trigger the vulnerable code path. Network segmentation and access controls should be enforced to limit exposure of systems running HTMLDoc to untrusted inputs. Additionally, implementing memory protection mechanisms such as stack canaries, address space layout randomization, and heap metadata validation can provide additional defense in depth. The vulnerability aligns with CWE-121, heap-based buffer overflow, and represents a potential entry point for techniques described in the ATT&CK framework under T1059 for command and scripting interpreter and T1203 for exploitation for privilege escalation. Regular security assessments and vulnerability scanning should be conducted to identify similar memory corruption issues in other components of the application stack that may present comparable risks.