{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/products/barebox--2026.04.0/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[{"cvss":8.4,"id":"CVE-2026-34963"}],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["barebox (\u003c 2026.04.0)"],"_cs_severities":["high"],"_cs_tags":["memory-safety","heap-overflow","bootloader"],"_cs_type":"threat","_cs_vendors":["barebox"],"content_html":"\u003cp\u003eCVE-2026-34963 identifies memory-safety vulnerabilities within the EFI PE loader of barebox versions prior to 2026.04.0. The vulnerability stems from an integer overflow during the computation of virtual image size, utilizing 32-bit arithmetic on section VirtualAddress and size values, which can result in an undersized heap allocation. Additionally, the PE section loading logic lacks sufficient validation to ensure that the sum of PointerToRawData and the copied size remains within the PE file buffer. Successful exploitation requires an attacker to supply a malicious EFI PE binary via TFTP, USB, SD card, or network boot. This could lead to a heap buffer overflow or out-of-bounds read from heap memory, ultimately enabling arbitrary code execution within the bootloader context.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker crafts a malicious EFI PE binary containing a crafted PE header and sections.\u003c/li\u003e\n\u003cli\u003eThe attacker provides the malicious EFI PE binary to the target system through a bootable medium (TFTP, USB, SD card, or network boot).\u003c/li\u003e\n\u003cli\u003eThe barebox bootloader initiates the EFI PE loader to process the provided binary.\u003c/li\u003e\n\u003cli\u003eDuring virtual image size computation, the 32-bit arithmetic on section VirtualAddress and size values causes an integer overflow, leading to an undersized heap allocation.\u003c/li\u003e\n\u003cli\u003eThe PE section loading logic fails to validate that the sum of \u003ccode\u003ePointerToRawData\u003c/code\u003e and the copied size remains within the bounds of the PE file buffer.\u003c/li\u003e\n\u003cli\u003eThe vulnerable \u003ccode\u003ememcpy\u003c/code\u003e function writes data beyond the allocated heap buffer, resulting in a heap buffer overflow.\u003c/li\u003e\n\u003cli\u003eAlternatively, the vulnerable logic attempts to read data from outside the bounds of the PE file, resulting in an out-of-bounds read from heap memory.\u003c/li\u003e\n\u003cli\u003eBy carefully crafting the malicious PE binary, the attacker can overwrite critical data structures in memory or inject and execute arbitrary code within the bootloader context.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of CVE-2026-34963 can lead to arbitrary code execution within the barebox bootloader environment. This allows an attacker to gain complete control over the affected system during the boot process. This can lead to data theft, system compromise, or the installation of persistent malware. The number of affected systems depends on the deployment of vulnerable barebox versions.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eUpgrade to barebox version 2026.04.0 or later to remediate CVE-2026-34963.\u003c/li\u003e\n\u003cli\u003eMonitor boot processes for attempts to load EFI PE binaries from untrusted sources (TFTP, USB, SD card, network boot), potentially correlating with network connection logs to TFTP servers.\u003c/li\u003e\n\u003cli\u003eDeploy the Sigma rule \u0026ldquo;Detect Suspicious EFI PE Binary Load\u0026rdquo; to detect potential exploitation attempts by monitoring process execution.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-11T23:21:42Z","date_published":"2026-05-11T23:21:42Z","id":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-34963-barebox-overflow/","summary":"barebox versions prior to 2026.04.0 are vulnerable to memory-safety issues in the EFI PE loader (CVE-2026-34963), potentially allowing code execution via malicious EFI PE binaries.","title":"barebox EFI PE Loader Memory-Safety Vulnerabilities (CVE-2026-34963)","url":"https://feed.craftedsignal.io/briefs/2026-05-cve-2026-34963-barebox-overflow/"}],"language":"en","title":"CraftedSignal Threat Feed — Barebox (\u003c 2026.04.0)","version":"https://jsonfeed.org/version/1.1"}