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CVE-2026-98839— vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，以下漏洞已得到修复： vt（虚拟终端）选择机制：修复了 函数中的无符号整数下溢及由此引发的 slab 越界读取问题。 在 函数中，循环每次迭代会调用 ，复制 字节的数据，并将 增加 。 由于选择互斥锁（ ）在循环内部被释放：当行规约（line discipline）缓冲区填满时， 会阻塞在 上等待。此时，一个并发的 （具体为 ）ioctl 调用可能将 替换为一个更短的选择区域，从而将 减小到低于当前的 值。 当 恢复执行时，表达式 作为无符号整数发生下溢，变为一个较大的正数值。这导致后续调用

AI Predicted 7.8 Difficulty: Hard EPSS 0.17% · P5

Affected Version Matrix 22

VendorProduct Version RangeStatus
Linux Linux e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2< 037d7e3ca5c593092f4b0d471eb869a85cbddde0 affected
e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2< 619c6d7dd76fff15a9714fbf02ce299b737f01a2 affected
e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2< 39495ef5d6f8019e62d65807f217a7ca8232727a affected
54c522782fd11a720f959ee9cb5a15bb9580343d affected
05c508edc9d0b44e4706d3c2cf14ee12aac210d2 affected
e5be0e24ffc7f5783a3864b5b958088ed15be9e8 affected
a4719f6d07b2c63223f7452c435c5f578f105cfe affected
b4492f1e7456bd162714c0ec2815c2749d930844 affected
… +14 more rows
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I. Basic Information for CVE-2026-98839

Vulnerability Information
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Vulnerability Title
vt: selection: Fix unsigned underflow and slab-out-of-bounds read in paste_selection()
Source: CVE Program / CVE List V5
Vulnerability Description
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> ==================================================================
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 ~ 037d7e3ca5c593092f4b0d471eb869a85cbddde0 -
Linux Linux 5.6 -

II. Public POCs for CVE-2026-98839

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III. Intelligence Information for CVE-2026-98839

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Patches & Fixes for CVE-2026-98839 (3)

Same Patch Batch · Linux · 2026-10-18 · 435 CVEs total

CVE-2026-98719 KVM: SEV: Nullify "have run CPUs" mask pointer when freeing it
CVE-2026-98732 Bluetooth: btintel: fix buffer over-read in btintel_hw_error()
CVE-2026-98731 Bluetooth: btintel_pcie: fix plen overflow in btintel_pcie_recv_frame()
CVE-2026-98730 Bluetooth: btintel_pcie: reject oversized TX packets in send_frame()
CVE-2026-98729 x86/mm: Don't apply va_align to hugetlb mappings on AMD F15h
CVE-2026-98728 tpm: fix off-by-four bounds check in tpm2_get_random()
CVE-2026-98727 nvme-multipath: set BLK_FEAT_ZONED only after the zone info is known
CVE-2026-98726 nvme-multipath: fix underflow in ANA log bounds checks
CVE-2026-98725 nvmet-auth: fix out-of-bounds write in nvmet_auth_challenge()
CVE-2026-98724 nvmet: pci-epf: reject too-short SGL segments
CVE-2026-98723 nvmet: copy the hostid into the ctrl before creating PR pc_refs
CVE-2026-98722 mtd: block2mtd: Fix divide error when erase_size is zero
CVE-2026-98721 mtd: rawnand: cadence: Initialize IRQ state before requesting IRQ
CVE-2026-98720 KVM: nVMX: Force MSR bitmap refresh if runtime eVMCS controls are modified
CVE-2026-98707 wifi: mac80211: shut down RX BA session timer on teardown
CVE-2026-98711 wifi: cw1200: fix TX padding OOB read leaking heap data to device
CVE-2026-98710 wifi: iwlegacy: 3945: free EEPROM data on remove
CVE-2026-98709 wifi: mac80211: count only matching reservations in reserved switch
CVE-2026-98712 KVM: arm64: vgic: Take a refcount on IRQs referenced by last_lr_irq
CVE-2026-98708 wifi: mac80211: keep paired old chanctx alive

Showing top 20 of 435 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-98839

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