CVE-2025-26519
📋 TL;DR
This vulnerability in musl libc allows attackers to trigger an out-of-bounds write during EUC-KR to UTF-8 iconv conversion, potentially leading to memory corruption and arbitrary code execution. It affects systems using musl libc versions 0.9.13 through 1.2.5, including Alpine Linux and other lightweight Linux distributions.
💻 Affected Systems
- musl libc
- Alpine Linux
- Docker containers using Alpine base images
- Embedded Linux systems using musl
📦 What is this software?
Musl by Musl Libc
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crashes (denial of service) or limited memory corruption affecting specific processes.
If Mitigated
Contained process crashes with no privilege escalation if proper sandboxing and memory protections are enabled.
🎯 Exploit Status
Exploitation requires specific conditions: attacker-controlled EUC-KR text being converted via iconv.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: musl libc 1.2.6
Vendor Advisory: https://www.openwall.com/lists/oss-security/2025/02/13/2
Restart Required: No
Instructions:
1. Update musl libc to version 1.2.6 or later. 2. For Alpine Linux: run 'apk update && apk upgrade musl'. 3. Rebuild any containers or applications using vulnerable musl versions.
🔧 Temporary Workarounds
Disable EUC-KR iconv conversion
allPrevent processing of EUC-KR text through iconv if not required.
Input validation
allValidate and sanitize all text input before iconv conversion.
🧯 If You Can't Patch
- Implement strict input validation for all text conversion operations
- Use application sandboxing/containerization to limit potential damage
🔍 How to Verify
Check if Vulnerable:
Check musl libc version: 'ldd --version' or 'musl-gcc --version'Check Version:
ldd --version 2>&1 | grep -i muslVerify Fix Applied:
Verify musl version is 1.2.6 or later using version check command📡 Detection & Monitoring
Log Indicators:
- Application crashes during text conversion
- Segmentation faults in processes using iconv
Network Indicators:
- Unusual EUC-KR encoded traffic to applications
SIEM Query:
process:crash AND (iconv OR musl OR text_conversion)🔗 References
- https://git.musl-libc.org/cgit/musl/commit/?id=c47ad25ea3b484e10326f933e927c0bc8cded3da
- https://git.musl-libc.org/cgit/musl/commit/?id=e5adcd97b5196e29991b524237381a0202a60659
- https://www.openwall.com/lists/oss-security/2025/02/13/2
- http://www.openwall.com/lists/oss-security/2025/02/13/2
- http://www.openwall.com/lists/oss-security/2025/02/13/3
- http://www.openwall.com/lists/oss-security/2025/02/13/4
- http://www.openwall.com/lists/oss-security/2025/02/13/5
- http://www.openwall.com/lists/oss-security/2025/02/14/5
- http://www.openwall.com/lists/oss-security/2025/02/14/6
