Memcached SASL Password Timing Side Channel Attack

CVE-2026-47784 is a timing side-channel vulnerability in memcached's SASL authentication mechanism that affects versions before 1.6.42. The flaw exists in the sasl_server_userdb_checkpass function, which uses memcmp—a function that compares memory byte-by-byte and returns on first mismatch—to validate SASL passwords. This implementation allows attackers to infer correct password characters by measuring response times: correct characters take longer to reject than incorrect ones, enabling password recovery through statistical analysis. Organizations running memcached with SASL authentication enabled are affected, particularly those using memcached for session management, caching sensitive data, or distributed authentication systems where timing differences are measurable across network boundaries.

While Casky currently shows zero matching skills for this CVE, practitioners using Claude AI with extended reasoning capabilities would detect this attack pattern by analyzing credential validation workflows and authentication timing behavior. The vulnerability falls under CWE-208 (Observable Timing Discrepancy), which Claude's reasoning engine can identify through code pattern analysis, network traffic timing correlation, and authentication function review. A practitioner analyzing this threat would examine SASL authentication logs for repeated failed attempts, network packet captures showing consistent request patterns with timing variations, and source code review of comparison functions. Detection would focus on anomalous authentication probing activity that measures response time deltas, particularly from external or untrusted network segments, indicating an attacker performing statistical timing analysis to extract password information character-by-character.