{"id":"AZL-88985","summary":"CVE-2026-46209 affecting package kernel for versions less than 6.6.141.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/gem: Fix inconsistent plane dimension calculation in drm_gem_fb_init_with_funcs()\n\ndrm_gem_fb_init_with_funcs() computes sub-sampled plane dimensions\nusing plain integer division:\n\n  unsigned int width  = mode_cmd-\u003ewidth  / (i ? info-\u003ehsub : 1);\n  unsigned int height = mode_cmd-\u003eheight / (i ? info-\u003evsub : 1);\n\nHowever, the ioctl-level framebuffer_check() in drm_framebuffer.c uses\ndrm_format_info_plane_width/height() which round up dimensions via\nDIV_ROUND_UP(). This inconsistency corrupts the subsequent GEM object\nsize check for certain pixel format and dimension combinations.\n\nFor example, with NV12 (vsub=2) and a 1-pixel-tall framebuffer the\nGEM size validation path sees height=0 instead of height=1. The\nexpression (height - 1) then wraps to UINT_MAX as an unsigned int,\ncausing min_size to overflow and wrap back to a small value. A tiny\nGEM object therefore passes the size guard, yet when the GPU accesses\nthe chroma plane it will read or write memory beyond the object's\nbounds.\n\nFix by replacing the open-coded divisions with drm_format_info_plane_width()\nand drm_format_info_plane_height(), which use DIV_ROUND_UP() and match\nthe calculation already used in framebuffer_check().","modified":"2026-08-28T17:47:35.043568813Z","published":"2026-05-28T10:16:36Z","upstream":["CVE-2026-46209"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46209"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.141.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-88985.json"}}],"schema_version":"1.9.0"}