{"id":"CVE-2026-98839","published":"2026-10-18T16:17:38.170","lastModified":"2026-10-19T10:19:47.957","description":"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->receive_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->write_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 >= 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  <TASK>\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  </TASK>\n ==================================================================","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/037d7e3ca5c593092f4b0d471eb869a85cbddde0","tags":[]},{"url":"https://git.kernel.org/stable/c/39495ef5d6f8019e62d65807f217a7ca8232727a","tags":[]},{"url":"https://git.kernel.org/stable/c/619c6d7dd76fff15a9714fbf02ce299b737f01a2","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}