{"id":"AZL-104466","summary":"CVE-2026-97604 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: vfb: defer cleanup until the last reference\n\nFBIOGETCMAP takes a shallow snapshot of info-\u003ecmap and performs the\nusercopy after dropping info-\u003elock. vfb_remove() frees the colormap\nimmediately after unregistering the framebuffer, even when an open file\nstill holds a reference to fb_info. A concurrent driver unbind can\ntherefore free the colormap while the ioctl copies it to userspace.\n\nKASAN reports:\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user\n  Read of size 512 by task poc/125\n\n   _copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24)\n   fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211)\n   do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114)\n\n   Allocated by task 1:\n   fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108)\n   vfb_probe (drivers/video/fbdev/vfb.c:459)\n\n   Freed by task 124:\n   fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151)\n   vfb_remove (drivers/video/fbdev/vfb.c:489)\n\nunregister_framebuffer() drops the registration reference, and fbdev calls\nfb_destroy after the last put_fb_info(). Move the registered framebuffer's\ncleanup into an fb_destroy callback so its colormap and screen buffer stay\nalive until all file references have been released.","modified":"2026-09-27T05:34:32Z","published":"2026-09-25T11:17:14Z","upstream":["CVE-2026-97604"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97604"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-104466.json"}}],"schema_version":"1.9.0"}