{"id":"CVE-2026-98839","state":"PUBLISHED","title":"vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()","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 ==================================================================","publishedAt":"2026-10-18T15:50:11.869Z","updatedAt":"2026-10-19T09:26:31.558Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2","status":"affected","lessThan":"037d7e3ca5c593092f4b0d471eb869a85cbddde0","versionType":"git"},{"version":"e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2","status":"affected","lessThan":"619c6d7dd76fff15a9714fbf02ce299b737f01a2","versionType":"git"},{"version":"e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2","status":"affected","lessThan":"39495ef5d6f8019e62d65807f217a7ca8232727a","versionType":"git"},{"version":"54c522782fd11a720f959ee9cb5a15bb9580343d","status":"affected","versionType":"git"},{"version":"05c508edc9d0b44e4706d3c2cf14ee12aac210d2","status":"affected","versionType":"git"},{"version":"e5be0e24ffc7f5783a3864b5b958088ed15be9e8","status":"affected","versionType":"git"},{"version":"a4719f6d07b2c63223f7452c435c5f578f105cfe","status":"affected","versionType":"git"},{"version":"b4492f1e7456bd162714c0ec2815c2749d930844","status":"affected","versionType":"git"},{"version":"9a9c13ad21a8220cb70c9807a920f43520515f94","status":"affected","versionType":"git"},{"version":"8c368d36878e2fc99285279fc5e14b3d3cb8947c","status":"affected","versionType":"git"},{"version":"3.16.83","status":"affected","lessThan":"3.17","versionType":"semver"},{"version":"4.4.216","status":"affected","lessThan":"4.5","versionType":"semver"},{"version":"4.9.216","status":"affected","lessThan":"4.10","versionType":"semver"},{"version":"4.14.173","status":"affected","lessThan":"4.15","versionType":"semver"},{"version":"4.19.109","status":"affected","lessThan":"4.20","versionType":"semver"},{"version":"5.4.25","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.5.9","status":"affected","lessThan":"5.6","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/vt/selection.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.6","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/vt/selection.c"]}],"references":["https://git.kernel.org/stable/c/037d7e3ca5c593092f4b0d471eb869a85cbddde0","https://git.kernel.org/stable/c/619c6d7dd76fff15a9714fbf02ce299b737f01a2","https://git.kernel.org/stable/c/39495ef5d6f8019e62d65807f217a7ca8232727a"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98839.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98839","state":"PUBLISHED","datePublished":"2026-10-18T15:50:11.869Z","dateUpdated":"2026-10-19T09:26:31.558Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.373Z"},"containers":{"cna":{"title":"vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()","descriptions":[{"lang":"en","value":"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 =================================================================="}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2","status":"affected","lessThan":"037d7e3ca5c593092f4b0d471eb869a85cbddde0","versionType":"git"},{"version":"e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2","status":"affected","lessThan":"619c6d7dd76fff15a9714fbf02ce299b737f01a2","versionType":"git"},{"version":"e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2","status":"affected","lessThan":"39495ef5d6f8019e62d65807f217a7ca8232727a","versionType":"git"},{"version":"54c522782fd11a720f959ee9cb5a15bb9580343d","status":"affected","versionType":"git"},{"version":"05c508edc9d0b44e4706d3c2cf14ee12aac210d2","status":"affected","versionType":"git"},{"version":"e5be0e24ffc7f5783a3864b5b958088ed15be9e8","status":"affected","versionType":"git"},{"version":"a4719f6d07b2c63223f7452c435c5f578f105cfe","status":"affected","versionType":"git"},{"version":"b4492f1e7456bd162714c0ec2815c2749d930844","status":"affected","versionType":"git"},{"version":"9a9c13ad21a8220cb70c9807a920f43520515f94","status":"affected","versionType":"git"},{"version":"8c368d36878e2fc99285279fc5e14b3d3cb8947c","status":"affected","versionType":"git"},{"version":"3.16.83","status":"affected","lessThan":"3.17","versionType":"semver"},{"version":"4.4.216","status":"affected","lessThan":"4.5","versionType":"semver"},{"version":"4.9.216","status":"affected","lessThan":"4.10","versionType":"semver"},{"version":"4.14.173","status":"affected","lessThan":"4.15","versionType":"semver"},{"version":"4.19.109","status":"affected","lessThan":"4.20","versionType":"semver"},{"version":"5.4.25","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.5.9","status":"affected","lessThan":"5.6","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/vt/selection.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.6","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/tty/vt/selection.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/037d7e3ca5c593092f4b0d471eb869a85cbddde0"},{"url":"https://git.kernel.org/stable/c/619c6d7dd76fff15a9714fbf02ce299b737f01a2"},{"url":"https://git.kernel.org/stable/c/39495ef5d6f8019e62d65807f217a7ca8232727a"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:26:31.558Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.16.83"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.4.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.14.173"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.19.109"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.25"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.5.9"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}