Password inference via nonconstant-time SASL comparison
Published May 20, 2026 · Updated May 20, 2026
Observable timing discrepancy in memcached before 1.6.42 allows remote attackers to infer SASL password data through authentication timing. sasl_server_userdb_checkpass compares submitted and stored passwords with memcmp, which returns after the first differing byte instead of operating in constant time. The path requires a SASL password-database build, the -S option, and repeated network authentication attempts; the flaw indirectly discloses password information.
Summary
What happened
Observable timing discrepancy in memcached before 1.6.42 allows remote attackers to infer SASL password data through authentication timing. sasl_server_userdb_checkpass compares submitted and stored passwords with memcmp, which returns after the first differing byte instead of operating in constant time. The path requires a SASL password-database build, the -S option, and repeated network authentication attempts; the flaw indirectly discloses password information.
The record
- CVE
- CVE-2026-47784
- Published
- May 20, 2026
- Updated
- May 20, 2026
- Vendor
- Memcached
- Product
- memcached
- Classifications
- CWE-208, T1110.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 20, 2026CVE publishedPublication date reported by the CVE source.
- May 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.6.42
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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