CVE-2026-77151 in Ech0
Summary
by MITRE • 08/20/2026
A security flaw has been discovered in lin-snow Ech0 up to 5.4.1. Affected by this issue is the function MD5Encrypt of the file internal/util/crypto/crypto.go. Performing a manipulation results in risky cryptographic algorithm. Remote exploitation of the attack is possible. The complexity of an attack is rather high. The exploitation is known to be difficult. Upgrading to version 5.4.2 can resolve this issue. The patch is named 9ce19a3b0d0765086a655f45d3a706ec1810404f. It is recommended to upgrade the affected component.
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified in lin-snow Ech0 versions up to 5.4.1 represents a significant weakness in cryptographic implementation, specifically within the MD5Encrypt function located in the internal/util/crypto/crypto.go file. This flaw stems from the use of the Message Digest algorithm 5 (MD5), which is widely recognized by security experts and industry standards as cryptographically broken and unsuitable for further use. The primary issue lies not necessarily in a logic error that allows direct code execution, but rather in the reliance on an outdated hashing mechanism that fails to meet modern security requirements for integrity verification and password storage. By continuing to utilize MD5, the application exposes itself to theoretical collision attacks and pre-image attacks, which can undermine the confidentiality and integrity of data processed by this module. This classification aligns with CWE-328, Use of Weak Hash, indicating that the software employs a cryptographic hash function that is not considered secure against determined adversaries.
From an operational perspective, while remote exploitation is technically possible due to the nature of the affected component being accessible over network interfaces or through API calls, the complexity of such an attack remains high. The difficulty in exploiting this vulnerability suggests that it does not provide immediate access control bypasses but rather degrades the overall security posture of the system. An attacker with sufficient resources and time could potentially leverage known MD5 weaknesses to generate collisions or reverse hashes if salt is not implemented correctly, although practical exploitation requires significant computational effort and specific conditions regarding how the hash output is utilized within the broader application logic. This scenario corresponds to ATT&CK technique T1608, which involves Forceful Cryptographic Attacks, where adversaries attempt to break cryptographic algorithms through brute force or mathematical weaknesses rather than exploiting implementation bugs like buffer overflows.
The impact of this vulnerability extends beyond immediate data compromise; it erodes trust in the system's ability to protect sensitive information such as user credentials, session tokens, or integrity checks for configuration files. If MD5 hashes are used for password storage without adequate salting and key stretching mechanisms like bcrypt or Argon2, attackers who obtain a database dump could perform offline brute-force attacks with high efficiency due to the speed of MD5 computations. Furthermore, if these hashes are used for verifying file integrity or digital signatures, an attacker might craft malicious inputs that produce the same hash as legitimate ones, leading to unauthorized modifications being accepted by the system without detection. This undermines the fundamental security principles of non-repudiation and data integrity essential for robust application architecture.
To mitigate this risk, it is strongly recommended to upgrade lin-snow Ech0 to version 5.4.2 or later, which incorporates the patch identified as commit 9ce19a3b0d0765086a655f45d3a706ec1810404f. This update replaces the insecure MD5 implementation with a stronger cryptographic alternative such as SHA-256 or SHA-3, depending on the specific use case within the application. In addition to upgrading, developers should conduct a thorough audit of all other instances where weak hashing algorithms might be employed across the codebase. It is also advisable to implement proper salting techniques if any legacy data needs to remain compatible during transition periods, although migrating entirely to modern standards like those defined in NIST SP 800-132 for password storage is the most effective long-term solution. Regular security assessments and dependency scanning should be integrated into the development lifecycle to prevent similar vulnerabilities from being introduced through third-party libraries or internal modules that rely on deprecated cryptographic primitives.