Bug 2426180 (CVE-2023-54186)

Summary: CVE-2023-54186 kernel: usb: typec: altmodes/displayport: fix pin_assignment_show
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-12-30 13:14:37 UTC 
In the Linux kernel, the following vulnerability has been resolved:

usb: typec: altmodes/displayport: fix pin_assignment_show

This patch fixes negative indexing of buf array in pin_assignment_show
when get_current_pin_assignments returns 0 i.e. no compatible pin
assignments are found.

BUG: KASAN: use-after-free in pin_assignment_show+0x26c/0x33c
...
Call trace:
dump_backtrace+0x110/0x204
dump_stack_lvl+0x84/0xbc
print_report+0x358/0x974
kasan_report+0x9c/0xfc
__do_kernel_fault+0xd4/0x2d4
do_bad_area+0x48/0x168
do_tag_check_fault+0x24/0x38
do_mem_abort+0x6c/0x14c
el1_abort+0x44/0x68
el1h_64_sync_handler+0x64/0xa4
el1h_64_sync+0x78/0x7c
pin_assignment_show+0x26c/0x33c
dev_attr_show+0x50/0xc0
Comment 1 Alexander B 2025-12-31 03:26:32 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025123026-CVE-2023-54186-a9c9@gregkh/T