{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/timing-side-channel/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":8.1,"id":"CVE-2026-47783"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":[],"_cs_severities":["medium"],"_cs_tags":["timing side channel","information disclosure","memcached"],"_cs_type":"threat","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eCVE-2026-47783 is a security vulnerability affecting memcached versions prior to 1.6.42. The vulnerability lies in the SASL (Simple Authentication and Security Layer) password database authentication mechanism. Specifically, the \u003ccode\u003esasl_server_userdb_checkpass\u003c/code\u003e function prematurely exits a loop upon encountering a valid username. This behavior introduces a timing side channel, where the time taken to process an authentication request can reveal information about the existence of usernames in the database. An attacker could exploit this timing difference to enumerate valid usernames. This vulnerability impacts systems where memcached is configured to use SASL authentication with a password database, and successful exploitation could lead to unauthorized information disclosure.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker sends an authentication request with a potential username.\u003c/li\u003e\n\u003cli\u003eThe \u003ccode\u003esasl_server_userdb_checkpass\u003c/code\u003e function in memcached is invoked.\u003c/li\u003e\n\u003cli\u003eThe function iterates through the list of valid usernames.\u003c/li\u003e\n\u003cli\u003eIf a matching username is found, the loop exits immediately.\u003c/li\u003e\n\u003cli\u003eThe time taken for the function to complete is measured by the attacker.\u003c/li\u003e\n\u003cli\u003eThe attacker repeats the process with different usernames, observing the timing variations.\u003c/li\u003e\n\u003cli\u003eBy analyzing the timing data, the attacker identifies usernames that cause a faster response.\u003c/li\u003e\n\u003cli\u003eThe faster response indicates a valid username, allowing the attacker to enumerate valid usernames.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-47783 allows an attacker to enumerate valid usernames in the memcached SASL password database. While it does not directly expose passwords, knowing valid usernames significantly weakens the security posture. This information can then be used in subsequent brute-force or credential-stuffing attacks against the memcached instance or other services where the same usernames are used. The impact is heightened in environments where memcached stores sensitive data and is protected by SASL authentication.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUpgrade memcached to version 1.6.42 or later to patch CVE-2026-47783.\u003c/li\u003e\n\u003cli\u003eMonitor memcached logs for unusual authentication patterns or attempts to enumerate usernames. Deploy the Sigma rule \u003ccode\u003eDetect Memcached SASL Authentication Username Enumeration\u003c/code\u003e to detect potential exploitation attempts.\u003c/li\u003e\n\u003cli\u003eConsider implementing rate limiting on authentication attempts to mitigate brute-force attacks that could leverage enumerated usernames.\u003c/li\u003e\n\u003cli\u003eIf possible, migrate away from SASL password database authentication to more secure authentication mechanisms like certificate-based authentication.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-21T07:13:41Z","date_published":"2026-05-21T07:13:41Z","id":"https://feed.craftedsignal.io/briefs/2026-05-memcached-timing-vuln/","summary":"CVE-2026-47783 is a timing side channel vulnerability in memcached before 1.6.42, affecting SASL password database authentication due to premature loop exit upon finding a valid username, potentially leading to information disclosure.","title":"CVE-2026-47783: memcached Timing Side Channel Vulnerability in SASL Authentication","url":"https://feed.craftedsignal.io/briefs/2026-05-memcached-timing-vuln/"}],"language":"en","title":"CraftedSignal Threat Feed — Timing Side Channel","version":"https://jsonfeed.org/version/1.1"}