{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/edns/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":["cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*"],"_cs_cves":[{"cvss":7.5,"id":"CVE-2026-42944"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":[],"_cs_severities":["high"],"_cs_tags":["cve","heap-overflow","dns","edns","denial-of-service"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eOn May 21, 2026, Microsoft published information regarding CVE-2026-42944, a heap overflow vulnerability. This vulnerability stems from the processing of multiple NSID, COOKIE, and PADDING Extended DNS (EDNS) options. The specifics of the affected product and the precise attack vector remain undisclosed in the initial advisory. The vulnerability\u0026rsquo;s impact could lead to denial of service or potentially remote code execution. Further details will likely be released as they become available, but defenders should prepare for the potential of exploit development and in-the-wild attacks.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003cp\u003eGiven the limited information, the following attack chain is a hypothetical reconstruction based on typical heap overflow exploitation scenarios:\u003c/p\u003e\n\u003col\u003e\n\u003cli\u003eAn attacker crafts a malicious DNS packet containing multiple NSID, COOKIE, and PADDING EDNS options.\u003c/li\u003e\n\u003cli\u003eThe malicious DNS packet is sent to a vulnerable DNS server or client.\u003c/li\u003e\n\u003cli\u003eThe vulnerable software attempts to parse and process the EDNS options within the DNS packet.\u003c/li\u003e\n\u003cli\u003eDue to improper validation of the number or size of these options, a heap buffer is allocated based on attacker-controlled values.\u003c/li\u003e\n\u003cli\u003eWhen writing the EDNS options into the heap buffer, the software overflows the buffer due to the excessive number and/or size of NSID, COOKIE, and PADDING options.\u003c/li\u003e\n\u003cli\u003eThe heap overflow corrupts adjacent memory structures, potentially overwriting function pointers or critical data.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the memory corruption to achieve arbitrary code execution or cause a denial-of-service condition.\u003c/li\u003e\n\u003cli\u003eIf code execution is achieved, the attacker can install malware, exfiltrate data, or pivot to other systems.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-42944 could lead to a denial-of-service condition on affected DNS servers or clients, disrupting network services. In a more severe scenario, the vulnerability may allow for remote code execution, granting an attacker the ability to gain control of the compromised system. This could enable data theft, malware deployment, or further lateral movement within the network. The extent of the impact depends on the specific product affected and the privileges of the exploited process.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMonitor network traffic for suspicious DNS packets containing an unusually large number of NSID, COOKIE, and PADDING EDNS options using a network intrusion detection system (NIDS).\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u003ccode\u003eDetect Suspicious DNS Packets with Excessive EDNS Options\u003c/code\u003e to identify potential exploitation attempts in network traffic.\u003c/li\u003e\n\u003cli\u003eOnce the affected product is identified by Microsoft, apply the security patch as soon as it becomes available to remediate CVE-2026-42944.\u003c/li\u003e\n\u003cli\u003eEnable DNS query logging to facilitate investigation of suspicious DNS traffic.\u003c/li\u003e\n\u003cli\u003eMonitor for unusual process behavior following DNS queries, such as unexpected process creation or network connections, using endpoint detection and response (EDR) solutions.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-21T07:14:09Z","date_published":"2026-05-21T07:14:09Z","id":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-42944/","summary":"Microsoft disclosed CVE-2026-42944, a heap overflow vulnerability related to the processing of multiple NSID, COOKIE, and PADDING EDNS options in an unspecified product.","title":"CVE-2026-42944: Heap Overflow with Multiple NSID, COOKIE, and PADDING EDNS Options","url":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-42944/"}],"language":"en","title":"CraftedSignal Threat Feed — Edns","version":"https://jsonfeed.org/version/1.1"}