{"id":"AZL-108933","summary":"CVE-2026-98839 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()\n\nIn paste_selection(), the loop copies min_t(unsigned int,\nvc_sel.buf_len - pasted,tty-\u003ereceive_room) bytes per iteration into\ntty_ldisc_receive_buf() and increments pasted += count.\n\nBecause the selection mutex (vc_sel.lock) is dropped inside the loop\nWhenever the line discipline buffer fills up and paste_selection()\nsleeps on tty-\u003ewrite_wait, a concurrent TIOCLINUX (TIOCL_SETSEL) ioctl\ncan replace vc_sel.buffer with a shorter selection and reduce\nvc_sel.buf_len below pasted.\n\nWhen paste_selection() resumes, vc_sel.buf_len - pasted underflows as an\nunsigned integer to a large positive value, causing\ntty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL, count) to read\nup to 4094 bytes out-of-bounds past the newly allocated vc_sel.buffer.\n\nFix this by terminating the loop when pasted \u003e= vc_sel.buf_len.\n\nKernel stack trace (Linux 7.3.0-rc3):\n ==================================================================\n BUG: KASAN: slab-out-of-bounds in n_tty_receive_buf_common+0xa01/0x1650\n Read of size 4094 at addr ffff888101c58010 by task kworker/u17:1/65\n Workqueue: events_unbound flush_to_ldisc\n Call Trace:\n  \u003cTASK\u003e\n  dump_stack_lvl+0x70/0xa0\n  print_report+0x153/0x4c6\n  kasan_report+0xf1/0x120\n  kasan_check_range+0x11c/0x200\n  __asan_memcpy+0x29/0x70\n  n_tty_receive_buf_common+0xa01/0x1650\n  tty_ldisc_receive_buf+0x66/0x110\n  tty_port_default_receive_buf+0x6b/0xb0\n  flush_to_ldisc+0x1b4/0x410\n  process_one_work+0x6ff/0x1110\n  worker_thread+0x4a8/0xb70\n  kthread+0x307/0x3e0\n  ret_from_fork+0x3ed/0x680\n  \u003c/TASK\u003e\n ==================================================================","modified":"2026-10-19T14:16:49.977767851Z","published":"2026-10-18T16:17:38Z","upstream":["CVE-2026-98839"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98839"}],"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-108933.json"}}],"schema_version":"1.9.0"}