CVE-2026-56582 in MyCloud
Summary
by MITRE • 07/21/2026
HCL MyCloud was affected by the SSL/TLS LUCKY13 Vulnerability. An attacker may exploit this vulnerability to decrypt sensitive information through a TLS/SSL padding oracle attack.
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Analysis
by VulDB Data Team • 07/21/2026
The SSL/TLS LUCKY13 vulnerability represents a critical cryptographic weakness that fundamentally undermines the security of Transport Layer Security implementations across numerous network devices including HCL MyCloud systems. This vulnerability stems from the improper handling of padding checks during the decryption process of TLS records, specifically affecting the way implementations verify the integrity of decrypted data. The flaw exploits timing variations in the padding validation process, creating a side-channel attack vector that allows malicious actors to systematically deduce cryptographic keys and sensitive information transmitted over secure connections.
The technical implementation of LUCKY13 resides within the cryptographic libraries that handle TLS protocol operations, where the vulnerability manifests through inconsistent timing behavior during padding verification. When an attacker performs a series of carefully crafted requests against a vulnerable system, they can observe subtle timing differences in how the system processes malformed padding data. These timing variations directly correlate to whether the padding is valid or invalid, enabling the attacker to perform a padding oracle attack that gradually reveals the plaintext content of encrypted communications. The vulnerability affects implementations that use CBC (Cipher Block Chaining) mode encryption combined with HMAC (Hash-based Message Authentication Code) for integrity verification.
The operational impact of this vulnerability on HCL MyCloud devices extends beyond simple data interception, as it provides attackers with the capability to perform deep packet inspection and decryption of sensitive user communications. Attackers can exploit this weakness to access personal files, authentication credentials, configuration data, and other confidential information stored or transmitted through the cloud storage platform. The vulnerability particularly affects systems where users store sensitive business data, personal documents, or authentication tokens that could be leveraged for further attacks within corporate networks or for identity theft purposes.
Security practitioners should implement immediate mitigations including updating firmware to versions that address the LUCKY13 vulnerability, disabling vulnerable TLS cipher suites that use CBC mode encryption, and implementing proper protocol-level restrictions on affected systems. Organizations must also consider deploying network monitoring solutions capable of detecting anomalous traffic patterns that may indicate exploitation attempts. According to CWE classification, this vulnerability maps to CWE-310: Cryptographic Issues, specifically addressing weak cryptographic implementations through improper padding validation. The ATT&CK framework categorizes this as a Privilege Escalation technique under T1566: Phishing for Information, where the initial compromise occurs through exploitation of cryptographic weaknesses rather than traditional social engineering methods. Long-term security measures should include migrating to modern cryptographic protocols such as TLS 1.3 that eliminate the vulnerability by removing CBC cipher suites and implementing constant-time padding checks to prevent timing-based side-channel attacks.