{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/products/windows-gdi/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":7.8,"id":"CVE-2026-35421"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Windows GDI"],"_cs_severities":["high"],"_cs_tags":["heap-overflow","code-execution","windows"],"_cs_type":"advisory","_cs_vendors":["Microsoft"],"content_html":"\u003cp\u003eCVE-2026-35421 is a heap-based buffer overflow vulnerability affecting the Windows Graphics Device Interface (GDI). An unauthorized, local attacker can exploit this vulnerability to execute arbitrary code on a vulnerable system. The CVSS v3.1 score is 7.8, indicating a high severity. The vulnerability exists because of insufficient bounds checking when handling specific image formats or drawing operations within the GDI. Successful exploitation allows the attacker to gain elevated privileges, potentially leading to full system compromise. The vulnerability was reported to Microsoft and assigned CVE-2026-35421.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains initial access to the target system through social engineering or other means.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious image file or drawing operation that triggers the buffer overflow within the Windows GDI.\u003c/li\u003e\n\u003cli\u003eThe attacker executes the malicious code through a program that leverages Windows GDI, such as a document viewer or image processing application.\u003c/li\u003e\n\u003cli\u003eWhen the application processes the malformed image or executes the crafted drawing command, the GDI attempts to allocate memory on the heap.\u003c/li\u003e\n\u003cli\u003eDue to the missing bounds checking, the allocation size is insufficient, resulting in a heap overflow.\u003c/li\u003e\n\u003cli\u003eThe overflow overwrites adjacent memory regions on the heap, potentially corrupting critical data structures.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the memory corruption to gain control of the program\u0026rsquo;s execution flow.\u003c/li\u003e\n\u003cli\u003eThe attacker injects and executes arbitrary code within the context of the vulnerable process, achieving local code execution with the privileges of the user.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-35421 allows a local attacker to execute arbitrary code on a vulnerable Windows system. This can lead to complete system compromise, including data theft, modification, or destruction. Given the wide use of the Windows GDI, numerous applications and services could potentially trigger the vulnerability if exposed to malicious image files or crafted drawing operations. An attacker could leverage this vulnerability to escalate privileges and move laterally within a network.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eApply the security update released by Microsoft to patch CVE-2026-35421 as referenced in the \u003ca href=\"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35421\"\u003eMicrosoft advisory\u003c/a\u003e.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Suspicious GDI Function Calls\u0026rdquo; to identify potential exploitation attempts based on abnormal GDI usage.\u003c/li\u003e\n\u003cli\u003eEnable process creation logging to provide detailed information on processes interacting with the Windows GDI, enhancing visibility for the provided Sigma rule.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-12T18:31:35Z","date_published":"2026-05-12T18:31:35Z","id":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-35421/","summary":"CVE-2026-35421 is a heap-based buffer overflow vulnerability in Windows Graphics Device Interface (GDI) that allows an unauthorized attacker to execute arbitrary code locally with elevated privileges.","title":"CVE-2026-35421 Heap-Based Buffer Overflow in Windows GDI","url":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-35421/"}],"language":"en","title":"CraftedSignal Threat Feed — Windows GDI","version":"https://jsonfeed.org/version/1.1"}