This vulnerability allows attackers to exploit the OpenSC software, specifically in the function sc_compacttlv_find_tag. The issue arises when the function processes untrusted data, potentially leading to memory corruption. The CVSS score of 3.9 indicates a low severity level, but organizations must recognize the potential risks involved, especially if the software is deployed in environments handling sensitive data.
Risk to organizations includes the possibility of attackers leveraging this vulnerability to influence the function's behavior, resulting in out-of-bounds pointers. This situation can lead to downstream effects, including memory corruption and potential system instability. Organizations using OpenSC should prioritize patching to version 0.27.0, which addresses this vulnerability.
As of now, there are no known exploits confirmed for CVE-2025-66038, but the potential for exploitation exists if the vulnerable function is provided with untrusted data. Therefore, organizations should actively monitor their systems and apply the necessary updates to mitigate any risks. Organizations should prioritize patching immediately.
Mitigation steps should include regular updates to the OpenSC software and implementing measures to validate data before it is processed by the sc_compacttlv_find_tag function. By taking these proactive steps, organizations can reduce their risk exposure.
Vulnerability Details
OpenSC is an open-source smart card tools and middleware. Prior to version 0.27.0, the function sc_compacttlv_find_tag searches a compact-TLV buffer for a given tag. In compact-TLV, a single byte encodes the tag (high nibble) and value length (low nibble). With a 1-byte buffer {0x0A}, the encoded element claims tag=0 and length=10, but no value bytes follow. Calling sc_compacttlv_find_tag with search tag 0x00 returns a pointer equal to buf+1 and outlen=10 without verifying that the claimed value length fits within the remaining buffer.
This issue has been patched in version 0.27.0. The vulnerability is classified as CWE-126, indicating a buffer over-read. The attack vector is physical, with a CVSS score of 3.9 representing low severity. The function has a high attack complexity, requiring no privileges or user interaction.
Technical Analysis
The root cause of this vulnerability stems from the failure to properly validate the length of the data being processed in the sc_compacttlv_find_tag function. Specifically, when the function is called with untrusted data, it can return out-of-bounds pointers. This behavior can lead to memory corruption when subsequent code attempts to dereference these pointers.
The attack vector is classified as physical, meaning an attacker must have physical access to the smart card or device. The complexity of the attack is high, as it requires specific conditions to be met for exploitation. The function does not require any privileges, and no user interaction is needed to trigger the vulnerability.
Risk & Impact Analysis
Real-world deployment risk is moderate due to the specificity of the requirements for exploitation. However, organizations using OpenSC should understand that this vulnerability can lead to memory corruption, potentially compromising the integrity of the system and leading to unexpected behavior.
The blast radius is limited to systems where OpenSC is deployed, particularly those handling untrusted data, such as data read from cards or files. The urgency for organizations to address this vulnerability is moderate, given the CVSS score of 3.9 and the lack of active exploitation reports. Organizations should schedule remediation at their earliest convenience.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The versions affected by this vulnerability are all versions of OpenSC prior to version 0.27.0.
Mitigation & Remediation
To mitigate this vulnerability, organizations should upgrade OpenSC to version 0.27.0 or later. In addition, implementing input validation techniques to ensure that only trusted data is processed by the sc_compacttlv_find_tag function can further reduce the risk.
Organizations may also consider conducting a thorough security assessment to identify other potential vulnerabilities in their systems. For comprehensive assessments, organizations can explore our application security assessment services.
Detection Guidance
To detect potential exploitation of this vulnerability, monitoring for unusual memory access patterns or application crashes related to the OpenSC software is recommended. Additionally, organizations should review logs for any anomalies that could indicate attempts to exploit the vulnerability.
AppSecure Threat Intelligence Insight
CVE-2025-66038 highlights an important aspect of software security: the need for rigorous input validation. As the use of smart card technology continues to grow, the risks associated with vulnerabilities like this can have significant implications for organizations handling sensitive data.
The trend toward underestimating low-severity vulnerabilities can lead to increased exposure. Security teams should implement proactive measures, including regular security assessments, to identify and mitigate such vulnerabilities. For continuous improvement in security posture, organizations are encouraged to engage in continuous penetration testing strategies.
Furthermore, organizations should stay informed about the latest vulnerabilities and their implications through resources like our blog on penetration testing methodology to adapt their security frameworks accordingly.
By prioritizing security awareness and adopting a proactive security approach, organizations can effectively mitigate the risks posed by vulnerabilities like CVE-2025-66038.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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