CVE-2026-68281
Received Received - Intake

Buffer Overflow in PowerVR DRM Driver

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: drm/imagination: Count paired job fence as dependency in prepare_job() The DRM scheduler's prepare_job() callback counts the remaining non-signaled native dependencies for a job, preventing job submission until those (plus job data and fence update) can fit in the job queue's CCCB. This means checking which dependencies can be waited upon in the firmware, i.e. whether they are backed by a UFO object, i.e. whether their drm_sched_fence::parent has been assigned to a pvr_queue_fence::base fence. That happens when the job owning the fence is submitted to the firmware. Paired geometry and fragment jobs are submitted at the same time, which means the dependency between them can't be checked this way before submission. Update job_count_remaining_native_deps() to take into account the dependency between paired jobs. This fixes cases where prepare_job() underestimated the space left in an almost full fragment CCCB, wrongly unblocking run_job(), which then returned early without writing the full sequence of commands to the CCCB. The above lead to kernel warnings such as the following and potentially job timeouts (depending on waiters on the missing commands): [ 375.702979] WARNING: drivers/gpu/drm/imagination/pvr_cccb.c:178 at pvr_cccb_write_command_with_header+0x2c4/0x330 [powervr], CPU#1: kworker/u16:3/47 [ 375.703160] Modules linked in: [ 375.703571] CPU: 1 UID: 0 PID: 47 Comm: kworker/u16:3 Tainted: G W 7.0.0-rc2-g817eb6b11ad5 #40 PREEMPT [ 375.703613] Tainted: [W]=WARN [ 375.703627] Hardware name: Texas Instruments AM625 SK (DT) [ 375.703645] Workqueue: powervr-sched drm_sched_run_job_work [gpu_sched] [ 375.703741] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 375.703764] pc : pvr_cccb_write_command_with_header+0x2c4/0x330 [powervr] [ 375.703847] lr : pvr_queue_submit_job_to_cccb+0x578/0xa70 [powervr] [ 375.703921] sp : ffff800084a97650 [ 375.703934] x29: ffff800084a97740 x28: 0000000000000958 x27: ffff80008565d000 [ 375.703979] x26: 0000000000000030 x25: ffff800084a97680 x24: 0000000000001000 [ 375.704017] x23: ffff800084a97820 x22: 1ffff00010952ecc x21: 0000000000000008 [ 375.704056] x20: 00000000000006a8 x19: ffff00002ff7da88 x18: 0000000000000000 [ 375.704093] x17: 0000000020020000 x16: 0000000000020000 x15: 0000000000000000 [ 375.704132] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 375.704168] x11: 000000000000f2f2 x10: 00000000f3000000 x9 : 00000000f3f3f3f3 [ 375.704206] x8 : 00000000f2f2f200 x7 : ffff700010952ecc x6 : 0000000000000008 [ 375.704243] x5 : 0000000000000000 x4 : 1ffff00010acba00 x3 : 0000000000000000 [ 375.704279] x2 : 0000000000000007 x1 : 0000000000000fff x0 : 000000000000002f [ 375.704317] Call trace: [ 375.704331] pvr_cccb_write_command_with_header+0x2c4/0x330 [powervr] (P) [ 375.704411] pvr_queue_submit_job_to_cccb+0x578/0xa70 [powervr] [ 375.704487] pvr_queue_run_job+0x3a4/0x990 [powervr] [ 375.704562] drm_sched_run_job_work+0x580/0xd48 [gpu_sched] [ 375.704623] process_one_work+0x520/0x1288 [ 375.704658] worker_thread+0x3f0/0xb3c [ 375.704680] kthread+0x334/0x3d8 [ 375.704706] ret_from_fork+0x10/0x20 [ 375.704736] ---[ end trace 0000000000000000 ]---

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68281
EUVD
EUVD-2026-55382

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
imagination powervr *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel affects the DRM scheduler in the PowerVR graphics driver. It involves paired geometry and fragment jobs that are submitted simultaneously. The scheduler incorrectly counts dependencies, leading to an underestimated job queue space. This causes kernel warnings and potential job timeouts due to missing command sequences.

Detection Guidance

This vulnerability is specific to the Linux kernel's DRM scheduler for PowerVR GPUs. Detection requires checking kernel logs for warnings related to CCCB (Command Queue Control Block) overflows or job timeouts in the powervr driver. Monitor logs with commands like dmesg | grep -i powervr or journalctl -k | grep -i powervr.

Impact Analysis

This vulnerability may cause system instability, such as kernel warnings and job timeouts, particularly in systems using PowerVR GPUs. It could lead to graphics rendering issues or crashes if paired jobs fail to execute properly due to incorrect dependency handling.

Mitigation Strategies

Apply the latest kernel update that includes the fix for this issue. If an update is not available, consider disabling the affected PowerVR GPU driver module (pvr) temporarily until a patch is applied.

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