In the Linux kernel, the following vulnerability has been resolved:

drm/display/dp_mst: Add protection against 0 vcpi

When releasing a timeslot there is a slight chance we may end up
with the wrong payload mask due to overflow if the delayed_destroy_work
ends up coming into play after a DP 2.1 monitor gets disconnected
which causes vcpi to become 0 then we try to make the payload =
~BIT(vcpi - 1) which is a negative shift. VCPI id should never
really be 0 hence skip changing the payload mask if VCPI is 0.

Otherwise it leads to
<7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc
[drm_display_helper]] port ffff888126ce9000 (3)
<4> [515.287267] -----------[ cut here ]-----------
<3> [515.287268] UBSAN: shift-out-of-bounds in
../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36
<3> [515.287271] shift exponent -1 is negative
<4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G
S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary)
<4> [515.287279] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
<4> [515.287279] Hardware name: ASUS System Product Name/PRIME Z790-P
WIFI, BIOS 1645 03/15/2024
<4> [515.287281] Workqueue: drm_dp_mst_wq drm_dp_delayed_destroy_work
[drm_display_helper]
<4> [515.287303] Call Trace:
<4> [515.287304] <TASK>
<4> [515.287306] dump_stack_lvl+0xc1/0xf0
<4> [515.287313] dump_stack+0x10/0x20
<4> [515.287316] __ubsan_handle_shift_out_of_bounds+0x133/0x2e0
<4> [515.287324] ? drm_atomic_get_private_obj_state+0x186/0x1d0
<4> [515.287333] drm_dp_atomic_release_time_slots.cold+0x17/0x3d
[drm_display_helper]
<4> [515.287355] mst_connector_atomic_check+0x159/0x180 [xe]
<4> [515.287546] drm_atomic_helper_check_modeset+0x4d9/0xfa0
<4> [515.287550] ? __ww_mutex_lock.constprop.0+0x6f/0x1a60
<4> [515.287562] intel_atomic_check+0x119/0x2b80 [xe]
<4> [515.287740] ? find_held_lock+0x31/0x90
<4> [515.287747] ? lock_release+0xce/0x2a0
<4> [515.287754] drm_atomic_check_only+0x6a2/0xb40
<4> [515.287758] ? drm_atomic_add_affected_connectors+0x12b/0x140
<4> [515.287765] drm_atomic_commit+0x6e/0xf0
<4> [515.287766] ? _pfx__drm_printfn_info+0x10/0x10
<4> [515.287774] drm_client_modeset_commit_atomic+0x25c/0x2b0
<4> [515.287794] drm_client_modeset_commit_locked+0x60/0x1b0
<4> [515.287795] ? mutex_lock_nested+0x1b/0x30
<4> [515.287801] drm_client_modeset_commit+0x26/0x50
<4> [515.287804] __drm_fb_helper_restore_fbdev_mode_unlocked+0xdc/0x110
<4> [515.287810] drm_fb_helper_hotplug_event+0x120/0x140
<4> [515.287814] drm_fbdev_client_hotplug+0x28/0xd0
<4> [515.287819] drm_client_hotplug+0x6c/0xf0
<4> [515.287824] drm_client_dev_hotplug+0x9e/0xd0
<4> [515.287829] drm_kms_helper_hotplug_event+0x1a/0x30
<4> [515.287834] drm_dp_delayed_destroy_work+0x3df/0x410
[drm_display_helper]
<4> [515.287861] process_one_work+0x22b/0x6f0
<4> [515.287874] worker_thread+0x1e8/0x3d0
<4> [515.287879] ? __pfx_worker_thread+0x10/0x10
<4> [515.287882] kthread+0x11c/0x250
<4> [515.287886] ? __pfx_kthread+0x10/0x10
<4> [515.287890] ret_from_fork+0x2d7/0x310
<4> [515.287894] ? __pfx_kthread+0x10/0x10
<4> [515.287897] ret_from_fork_asm+0x1a/0x30

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History

Wed, 27 May 2026 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-20
CWE-680
CWE-703

Wed, 27 May 2026 14:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: drm/display/dp_mst: Add protection against 0 vcpi When releasing a timeslot there is a slight chance we may end up with the wrong payload mask due to overflow if the delayed_destroy_work ends up coming into play after a DP 2.1 monitor gets disconnected which causes vcpi to become 0 then we try to make the payload = ~BIT(vcpi - 1) which is a negative shift. VCPI id should never really be 0 hence skip changing the payload mask if VCPI is 0. Otherwise it leads to <7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc [drm_display_helper]] port ffff888126ce9000 (3) <4> [515.287267] -----------[ cut here ]----------- <3> [515.287268] UBSAN: shift-out-of-bounds in ../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36 <3> [515.287271] shift exponent -1 is negative <4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary) <4> [515.287279] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER <4> [515.287279] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 1645 03/15/2024 <4> [515.287281] Workqueue: drm_dp_mst_wq drm_dp_delayed_destroy_work [drm_display_helper] <4> [515.287303] Call Trace: <4> [515.287304] <TASK> <4> [515.287306] dump_stack_lvl+0xc1/0xf0 <4> [515.287313] dump_stack+0x10/0x20 <4> [515.287316] __ubsan_handle_shift_out_of_bounds+0x133/0x2e0 <4> [515.287324] ? drm_atomic_get_private_obj_state+0x186/0x1d0 <4> [515.287333] drm_dp_atomic_release_time_slots.cold+0x17/0x3d [drm_display_helper] <4> [515.287355] mst_connector_atomic_check+0x159/0x180 [xe] <4> [515.287546] drm_atomic_helper_check_modeset+0x4d9/0xfa0 <4> [515.287550] ? __ww_mutex_lock.constprop.0+0x6f/0x1a60 <4> [515.287562] intel_atomic_check+0x119/0x2b80 [xe] <4> [515.287740] ? find_held_lock+0x31/0x90 <4> [515.287747] ? lock_release+0xce/0x2a0 <4> [515.287754] drm_atomic_check_only+0x6a2/0xb40 <4> [515.287758] ? drm_atomic_add_affected_connectors+0x12b/0x140 <4> [515.287765] drm_atomic_commit+0x6e/0xf0 <4> [515.287766] ? _pfx__drm_printfn_info+0x10/0x10 <4> [515.287774] drm_client_modeset_commit_atomic+0x25c/0x2b0 <4> [515.287794] drm_client_modeset_commit_locked+0x60/0x1b0 <4> [515.287795] ? mutex_lock_nested+0x1b/0x30 <4> [515.287801] drm_client_modeset_commit+0x26/0x50 <4> [515.287804] __drm_fb_helper_restore_fbdev_mode_unlocked+0xdc/0x110 <4> [515.287810] drm_fb_helper_hotplug_event+0x120/0x140 <4> [515.287814] drm_fbdev_client_hotplug+0x28/0xd0 <4> [515.287819] drm_client_hotplug+0x6c/0xf0 <4> [515.287824] drm_client_dev_hotplug+0x9e/0xd0 <4> [515.287829] drm_kms_helper_hotplug_event+0x1a/0x30 <4> [515.287834] drm_dp_delayed_destroy_work+0x3df/0x410 [drm_display_helper] <4> [515.287861] process_one_work+0x22b/0x6f0 <4> [515.287874] worker_thread+0x1e8/0x3d0 <4> [515.287879] ? __pfx_worker_thread+0x10/0x10 <4> [515.287882] kthread+0x11c/0x250 <4> [515.287886] ? __pfx_kthread+0x10/0x10 <4> [515.287890] ret_from_fork+0x2d7/0x310 <4> [515.287894] ? __pfx_kthread+0x10/0x10 <4> [515.287897] ret_from_fork_asm+0x1a/0x30
Title drm/display/dp_mst: Add protection against 0 vcpi
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-27T12:14:55.722Z

Reserved: 2026-05-08T13:14:33.087Z

Link: CVE-2025-71305

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-27T14:16:43.000

Modified: 2026-05-27T14:48:31.480

Link: CVE-2025-71305

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-27T16:15:05Z

Weaknesses