{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/cve-2026-42899/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":7.5,"id":"CVE-2026-42899"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["ASP.NET Core"],"_cs_severities":["medium"],"_cs_tags":["denial-of-service","asp.net","CVE-2026-42899"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eCVE-2026-42899 details a denial-of-service vulnerability affecting ASP.NET Core. The vulnerability stems from a loop with an unreachable exit condition, effectively creating an infinite loop. An unauthorized attacker can exploit this flaw to exhaust server resources, leading to a denial of service for legitimate users. Microsoft has acknowledged this vulnerability and assigned it a CVSS v3.1 score of 7.5, highlighting the potential impact. Exploitation occurs over a network, requiring no user interaction or privileges. This vulnerability poses a significant risk to web applications built on ASP.NET Core, potentially disrupting services and impacting availability. Defenders should prioritize patching and consider implementing mitigations to prevent exploitation.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker sends a specially crafted HTTP request to an ASP.NET Core endpoint.\u003c/li\u003e\n\u003cli\u003eThe request triggers the vulnerable code path containing the infinite loop.\u003c/li\u003e\n\u003cli\u003eThe application enters an infinite loop, consuming CPU resources.\u003c/li\u003e\n\u003cli\u003eAs the CPU usage increases, the server\u0026rsquo;s performance degrades.\u003c/li\u003e\n\u003cli\u003eThe server becomes unresponsive to legitimate user requests.\u003c/li\u003e\n\u003cli\u003eThe attacker continues to send malicious requests to maintain the denial of service.\u003c/li\u003e\n\u003cli\u003eThe server eventually exhausts its resources (CPU, memory).\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-42899 leads to a denial-of-service condition on ASP.NET Core applications. This can result in website unavailability, disrupted services, and potential financial losses due to downtime. The vulnerability can be exploited remotely without authentication, making it easily accessible to attackers. The impact is significant, as affected applications become unusable until the issue is resolved. The high CVSS score of 7.5 reflects the severity of the potential disruption and the relative ease of exploitation.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApply the security update provided by Microsoft to patch CVE-2026-42899 on all ASP.NET Core servers (reference: Microsoft Security Update Guide).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule provided below to detect potential exploitation attempts by monitoring for abnormal CPU utilization patterns (reference: Sigma rule).\u003c/li\u003e\n\u003cli\u003eMonitor web server logs for suspicious requests that might be triggering the infinite loop (reference: webserver logs).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-12T18:54:27Z","date_published":"2026-05-12T18:54:27Z","id":"https://feed.craftedsignal.io/briefs/2026-05-aspnet-dos/","summary":"CVE-2026-42899 describes an infinite loop vulnerability in ASP.NET Core that allows an unauthorized attacker to perform a denial of service attack over a network.","title":"CVE-2026-42899 - ASP.NET Core Infinite Loop Denial of Service","url":"https://feed.craftedsignal.io/briefs/2026-05-aspnet-dos/"}],"language":"en","title":"CraftedSignal Threat Feed — CVE-2026-42899","version":"https://jsonfeed.org/version/1.1"}