CVE-2025-2174 in libzvbi
Summary
by MITRE • 03/11/2025
A vulnerability was found in libzvbi up to 0.2.43. It has been declared as problematic. Affected by this vulnerability is the function vbi_strndup_iconv_ucs2 of the file src/conv.c. The manipulation of the argument src_length leads to integer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 0.2.44 is able to address this issue. The patch is named ca1672134b3e2962cd392212c73f44f8f4cb489f. It is recommended to upgrade the affected component. The code maintainer was informed beforehand about the issues. She reacted very fast and highly professional.
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Analysis
by VulDB Data Team • 10/03/2025
The vulnerability identified as CVE-2025-2174 represents a critical integer overflow condition within the libzvbi library version 0.2.43 and earlier, affecting the vbi_strndup_iconv_ucs2 function located in src/conv.c. This flaw arises from improper handling of the src_length argument which can lead to unpredictable behavior when the input parameter exceeds the maximum representable value for the integer type used in the function's implementation. The integer overflow occurs during the conversion process of UCS-2 encoded strings, creating a scenario where the calculated buffer size becomes negative or wraps around to a large positive value, ultimately resulting in memory corruption. The vulnerability is classified under CWE-190 as an integer overflow condition, specifically manifesting as an integer overflow in a signed integer context where the overflow leads to memory allocation issues.
The remote exploitability of this vulnerability makes it particularly concerning for systems that process external VBI (Video Broadcast Interface) data streams or handle user-provided content containing encoded text. Attackers can craft malicious input data with carefully manipulated src_length values that trigger the integer overflow during string conversion operations, potentially leading to buffer overflows, memory corruption, and arbitrary code execution. The public disclosure of the exploit means that threat actors can leverage this vulnerability without requiring specialized knowledge or access to the internal development processes. This aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where attackers exploit software vulnerabilities to execute malicious code on target systems. The vulnerability affects applications that rely on libzvbi for processing teletext and closed caption data, including media players, broadcast processing systems, and content management platforms.
The security implications extend beyond simple memory corruption as the integer overflow can be leveraged to bypass security mechanisms, manipulate program flow, or establish persistent access to affected systems. When the overflow occurs during buffer allocation, it can result in heap corruption that may allow attackers to control memory layout and potentially execute malicious payloads through crafted input sequences. The vulnerability affects systems processing VBI data such as television broadcast systems, digital media applications, and any software that utilizes libzvbi for text encoding conversion. The rapid response by the code maintainer, evidenced by the quick patch development and release, demonstrates a professional security response that aligns with best practices for vulnerability management and responsible disclosure.
The recommended remediation involves upgrading to libzvbi version 0.2.44, which contains the patch identified by commit hash ca1672134b3e2962cd392212c73f44f8f4cb489f. This patch specifically addresses the integer overflow condition by implementing proper bounds checking on the src_length parameter before performing any arithmetic operations that could lead to overflow. Organizations should conduct immediate vulnerability assessments to identify systems running affected versions of libzvbi and implement the upgrade as a priority. Additional mitigations include input validation at application layers, restricting external data processing, and implementing runtime protections such as address space layout randomization and stack canaries to reduce the exploitability of similar vulnerabilities. The patch addresses the root cause by ensuring that integer operations are performed with proper overflow detection and bounds validation, preventing the malicious manipulation of the src_length parameter from causing memory allocation failures that could be exploited for privilege escalation or denial of service attacks.