CVE-2025-26519
Remediation/Mitigation Strategy: CVE-2025-26519 - musl libc Out-of-Bounds Write
This document outlines the remediation and mitigation strategy for CVE-2025-26519, an out-of-bounds write vulnerability in musl libc.
1. Vulnerability Description:
- CVE ID: CVE-2025-26519
- Description: musl libc versions 0.9.13 through 1.2.5 (inclusive) are vulnerable to an out-of-bounds write. This vulnerability can be triggered when an attacker can influence or control the input to an
iconvconversion, specifically converting untrusted EUC-KR text to UTF-8. Maliciously crafted EUC-KR input can cause theiconvfunction to write data outside the bounds of the allocated buffer. - Affected Versions: musl libc 0.9.13 through 1.2.5
2. Severity:
- CVSS Score: 8.1 (High)
- CVSS Vector: AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (This is derived from the provided data: 8.1 Base Score, Network Attack Vector, Low Attack Complexity, No Privileges Required, User Interaction Required, Unchanged Scope, High Confidentiality Impact, High Integrity Impact, High Availability Impact)
- Severity Justification: The vulnerability allows for remote code execution if an attacker can convince a user to process malicious EUC-KR data. Successful exploitation can lead to complete compromise of the affected system. While User Interaction is Required, the exploitation path could be relatively simple (e.g., tricking a user into viewing a webpage or opening a file containing malicious EUC-KR).
3. Known Exploits:
- While specific exploit code is not mentioned in the provided data, the description clearly indicates that malicious EUC-KR input can trigger the out-of-bounds write. An attacker would need to craft input that causes the
iconvfunction to write past the buffer boundary during the EUC-KR to UTF-8 conversion. The exact details of how to reliably trigger the overflow would require further analysis of theiconvimplementation in musl libc.
4. Remediation Strategy:
The primary remediation strategy is to upgrade to a patched version of musl libc.
- Action: Upgrade to musl libc version 1.2.6 or later. This version contains the fix for CVE-2025-26519.
- Implementation:
- Identify affected systems: Determine which systems are using musl libc versions 0.9.13 through 1.2.5. This can be done through package management tools or by directly inspecting the
libc.sofile on the system. - Update musl libc: Use the system’s package manager to update musl libc. For example, on Alpine Linux:
apk update && apk upgrade musl. On systems using other package managers (e.g.,apt,yum), use the appropriate commands. - Rebuild dependent applications: After upgrading musl libc, it’s crucial to rebuild any applications that statically link against it. This ensures that they are using the patched version of the library. Dynamically linked applications may also require a restart to load the new libc version.
- Verification: After upgrading, verify the musl libc version to ensure the update was successful. Also, test the affected application with various EUC-KR inputs to confirm the vulnerability is no longer present.
- Identify affected systems: Determine which systems are using musl libc versions 0.9.13 through 1.2.5. This can be done through package management tools or by directly inspecting the
5. Mitigation Strategy (If immediate patching is not possible):
If an immediate upgrade is not feasible, the following mitigations can reduce the risk of exploitation:
- Input Validation: Implement strict input validation on any data that will be processed by
iconvusing EUC-KR as the source encoding. Sanitize or reject input that appears suspicious or malformed. This is a complex mitigation and may not be fully effective. - Disable or Restrict EUC-KR Conversions: If possible, disable the use of EUC-KR to UTF-8 conversions entirely. If this is not feasible, restrict its use to trusted sources only. This can significantly reduce the attack surface.
- Sandboxing: Run applications that process EUC-KR data within a sandboxed environment (e.g., using Docker, AppArmor, or SELinux). This can limit the impact of a successful exploit. This can limit the impact of a successful exploit by preventing it from accessing sensitive data or system resources.
- Monitor for Suspicious Activity: Implement monitoring to detect unusual activity related to
iconvcalls or memory usage patterns. This can help to identify and respond to potential exploitation attempts.
6. Communication:
- Communicate the vulnerability and remediation steps to all affected teams and stakeholders.
- Provide clear instructions on how to identify affected systems and apply the patch.
- Track the progress of the remediation efforts and report on the status.
7. Long-Term Prevention:
- Security Audits: Conduct regular security audits of code that uses
iconv, paying particular attention to the handling of untrusted input. - Fuzzing: Use fuzzing tools to test the robustness of
iconvimplementations against malformed input. - Stay Updated: Subscribe to security advisories for musl libc and other critical libraries.
- Secure Coding Practices: Enforce secure coding practices to prevent vulnerabilities in future code.
Disclaimer:
This remediation/mitigation strategy is based on the information provided and should be reviewed and adapted to your specific environment and risk profile. It is recommended to consult with security experts for further guidance. This is especially crucial for developing robust input validation, as crafting an effective filter against malicious EUC-KR input is difficult and prone to bypasses.
Assigner
- MITRE [email protected]
Date
- Published Date: 2025-02-14 00:00:00
- Updated Date: 2025-02-14 17:15:23