{"id":"AZL-50791","summary":"CVE-2024-50048 affecting package kernel 5.15.200.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbcon: Fix a NULL pointer dereference issue in fbcon_putcs\n\nsyzbot has found a NULL pointer dereference bug in fbcon.\nHere is the simplified C reproducer:\n\nstruct param {\n\tuint8_t type;\n\tstruct tiocl_selection ts;\n};\n\nint main()\n{\n\tstruct fb_con2fbmap con2fb;\n\tstruct param param;\n\n\tint fd = open(\"/dev/fb1\", 0, 0);\n\n\tcon2fb.console = 0x19;\n\tcon2fb.framebuffer = 0;\n\tioctl(fd, FBIOPUT_CON2FBMAP, &con2fb);\n\n\tparam.type = 2;\n\tparam.ts.xs = 0; param.ts.ys = 0;\n\tparam.ts.xe = 0; param.ts.ye = 0;\n\tparam.ts.sel_mode = 0;\n\n\tint fd1 = open(\"/dev/tty1\", O_RDWR, 0);\n\tioctl(fd1, TIOCLINUX, &param);\n\n\tcon2fb.console = 1;\n\tcon2fb.framebuffer = 0;\n\tioctl(fd, FBIOPUT_CON2FBMAP, &con2fb);\n\n\treturn 0;\n}\n\nAfter calling ioctl(fd1, TIOCLINUX, &param), the subsequent ioctl(fd, FBIOPUT_CON2FBMAP, &con2fb)\ncauses the kernel to follow a different execution path:\n\n set_con2fb_map\n  -\u003e con2fb_init_display\n   -\u003e fbcon_set_disp\n    -\u003e redraw_screen\n     -\u003e hide_cursor\n      -\u003e clear_selection\n       -\u003e highlight\n        -\u003e invert_screen\n         -\u003e do_update_region\n          -\u003e fbcon_putcs\n           -\u003e ops-\u003eputcs\n\nSince ops-\u003eputcs is a NULL pointer, this leads to a kernel panic.\nTo prevent this, we need to call set_blitting_type() within set_con2fb_map()\nto properly initialize ops-\u003eputcs.","modified":"2026-04-01T05:16:19.613528Z","published":"2024-10-21T20:15:17Z","upstream":["CVE-2024-50048"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-50048"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.15.200.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-50791.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}