CVE-2026-98839 (GCVE-0-2026-98839)
Vulnerability from cvelistv5
Published
2026-10-18 15:50
Modified
2026-10-19 09:26
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()
In paste_selection(), the loop copies min_t(unsigned int,
vc_sel.buf_len - pasted,tty->receive_room) bytes per iteration into
tty_ldisc_receive_buf() and increments pasted += count.
Because the selection mutex (vc_sel.lock) is dropped inside the loop
Whenever the line discipline buffer fills up and paste_selection()
sleeps on tty->write_wait, a concurrent TIOCLINUX (TIOCL_SETSEL) ioctl
can replace vc_sel.buffer with a shorter selection and reduce
vc_sel.buf_len below pasted.
When paste_selection() resumes, vc_sel.buf_len - pasted underflows as an
unsigned integer to a large positive value, causing
tty_ldisc_receive_buf(ld, vc_sel.buffer + pasted, NULL, count) to read
up to 4094 bytes out-of-bounds past the newly allocated vc_sel.buffer.
Fix this by terminating the loop when pasted >= vc_sel.buf_len.
Kernel stack trace (Linux 7.3.0-rc3):
==================================================================
BUG: KASAN: slab-out-of-bounds in n_tty_receive_buf_common+0xa01/0x1650
Read of size 4094 at addr ffff888101c58010 by task kworker/u17:1/65
Workqueue: events_unbound flush_to_ldisc
Call Trace:
<TASK>
dump_stack_lvl+0x70/0xa0
print_report+0x153/0x4c6
kasan_report+0xf1/0x120
kasan_check_range+0x11c/0x200
__asan_memcpy+0x29/0x70
n_tty_receive_buf_common+0xa01/0x1650
tty_ldisc_receive_buf+0x66/0x110
tty_port_default_receive_buf+0x6b/0xb0
flush_to_ldisc+0x1b4/0x410
process_one_work+0x6ff/0x1110
worker_thread+0x4a8/0xb70
kthread+0x307/0x3e0
ret_from_fork+0x3ed/0x680
</TASK>
==================================================================
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 Version: e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 Version: e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 Version: 54c522782fd11a720f959ee9cb5a15bb9580343d Version: 05c508edc9d0b44e4706d3c2cf14ee12aac210d2 Version: e5be0e24ffc7f5783a3864b5b958088ed15be9e8 Version: a4719f6d07b2c63223f7452c435c5f578f105cfe Version: b4492f1e7456bd162714c0ec2815c2749d930844 Version: 9a9c13ad21a8220cb70c9807a920f43520515f94 Version: 8c368d36878e2fc99285279fc5e14b3d3cb8947c Version: 3.16.83 ≤ Version: 4.4.216 ≤ Version: 4.9.216 ≤ Version: 4.14.173 ≤ Version: 4.19.109 ≤ Version: 5.4.25 ≤ Version: 5.5.9 ≤ |
||
{
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},
{
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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},
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}
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}
],
"cpeApplicability": [
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],
"negate": false,
"operator": "OR"
}
]
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],
"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-\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 =================================================================="
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T09:26:31.558Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
],
"title": "vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-98839",
"datePublished": "2026-10-18T15:50:11.869Z",
"dateReserved": "2026-09-25T10:25:14.373Z",
"dateUpdated": "2026-10-19T09:26:31.558Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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