PT-2026-43688 · Linux · Linux

Published

2026-05-27

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Updated

2026-05-27

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CVE-2025-71305

None

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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] <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

Related Identifiers

CVE-2025-71305

Affected Products

Linux