PT-2026-117058 · Linux · Linux
CVE-2026-98839
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Published
2026-10-18
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Updated
2026-10-18
None
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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: 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
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Related Identifiers
Affected Products
Linux