CVE-2026-68261 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
drm/imagination: fix error checking of pvr_vm_context_lookup()
Since pvr_vm_context_lookup() returns either NULL or a pointer, then stop using IS_ERR() for checking the return value.
Using IS_ERR() leads to the kernel oops reported below. It can be reproduced by passing an invalid VM context handle from userspace to the DRM_IOCTL_PVR_CREATE_CONTEXT ioctl.
[ 92.733119] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000148
[ 92.742042] Mem abort info:
[ 92.744890] ESR = 0x0000000096000004
[ 92.748686] EC = 0x25: DABT (current EL), IL = 32 bits
[ 92.754020] SET = 0, FnV = 0
[ 92.757154] EA = 0, S1PTW = 0
[ 92.760337] FSC = 0x04: level 0 translation fault
[ 92.765243] Data abort info:
[ 92.768129] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[ 92.773626] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 92.778763] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 92.784098] user pgtable: 4k pages, 48-bit VAs, pgdp=000000088ed23000
[ 92.790550] [0000000000000148] pgd=0000000000000000, p4d=0000000000000000
[ 92.797381] Internal error: Oops: 0000000096000004 [#1] SMP
[ 92.803027] Modules linked in: powervr
[ 92.852533] CPU: 0 UID: 0 PID: 409 Comm: triangle Not tainted 7.1.0-rc5-g98b46e693b91 #1 PREEMPT
[ 92.861385] Hardware name: Texas Instruments AM68 SK (DT)
[ 92.866766] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 92.873709] pc : pvr_vm_get_fw_mem_context+0x0/0xc [powervr]
[ 92.879376] lr : pvr_queue_create+0x26c/0x440 [powervr]
[ 92.884595] sp : ffff8000837fbb00
[ 92.887895] x29: ffff8000837fbb60 x28: 0000000000000000 x27: ffff8000837fbce8
[ 92.895015] x26: ffff000807f61a40 x25: ffff000807f61a00 x24: ffff000807f64400
[ 92.902135] x23: ffff00080a5ab000 x22: ffff800079b24730 x21: ffff000807f61800
[ 92.909254] x20: ffff00080999e680 x19: 0000000000000000 x18: 0000000000000000
[ 92.916373] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000001
[ 92.923492] x14: 0000000000000000 x13: 0000000000000002 x12: ffff80008145b298
[ 92.930611] x11: ffff8000844e5000 x10: ffff80008165a130 x9 : 0000000000000100
[ 92.937730] x8 : 0000000000000001 x7 : ffff0008076b27e0 x6 : ffff00080ec43b7c
[ 92.944850] x5 : ffff00080ec43b78 x4 : 0000000000000000 x3 : ffff00080999e680
[ 92.951968] x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
[ 92.959088] Call trace:
[ 92.961521] pvr_vm_get_fw_mem_context+0x0/0xc [powervr] (P)
[ 92.967173] pvr_context_create+0x190/0x410 [powervr]
[ 92.972218] pvr_ioctl_create_context+0x44/0x8c [powervr]
[ 92.977608] drm_ioctl_kernel+0xbc/0x124 [drm]
[ 92.982127] drm_ioctl+0x1f8/0x4dc [drm]
[ 92.986098] __arm64_sys_ioctl+0xac/0x104
[ 92.990102] invoke_syscall+0x54/0x10c
[ 92.993842] el0_svc_common.constprop.0+0x40/0xe0
[ 92.998532] do_el0_svc+0x1c/0x28
[ 93.001835] el0_svc+0x38/0x11c
[ 93.004969] el0t_64_sync_handler+0xa0/0xe4
[ 93.009139] el0t_64_sync+0x198/0x19c
[ 93.012792] Code: aa1703e0 d2800014 95cb0ba4 17ffffe8 (f940a400)
[ 93.018869] ---[ end trace 0000000000000000 ]---
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Analysis
by VulDB Data Team • 08/10/2026
The vulnerability resides in the Linux kernel's display subsystem, specifically within the drm/imagination driver component responsible for handling PowerVR graphics hardware. This issue manifests as an improper error checking mechanism when validating return values from the pvr_vm_context_lookup() function, which creates a critical condition leading to kernel oops and potential system instability. The root cause stems from the incorrect usage of IS_ERR() macro for checking return values that are either NULL or valid pointers rather than error codes, violating fundamental kernel programming practices.
The technical flaw occurs when userspace applications pass invalid VM context handles to the DRM_IOCTL_PVR_CREATE_CONTEXT ioctl interface. The pvr_vm_context_lookup() function returns either a valid pointer or NULL, but the code incorrectly applies IS_ERR() checking which is designed for functions returning error codes wrapped in pointer format. This mismatch causes the kernel to interpret valid NULL return values as error pointers, leading to subsequent dereference operations that trigger memory access violations at virtual address 0x148. The stack trace reveals the execution path through pvr_vm_get_fw_mem_context(), pvr_queue_create(), and ultimately into the DRM ioctl handling chain where the invalid pointer dereference occurs.
This vulnerability presents a significant operational impact as it allows potential attackers to trigger kernel oops conditions through crafted ioctl calls, effectively creating a denial-of-service scenario that can crash the entire system. The exploitability is relatively straightforward since it requires only passing an invalid VM context handle from userspace, making it accessible to unprivileged users who can leverage this to cause system instability or potentially escalate privileges depending on the broader attack surface. From an ATT&CK perspective, this maps to privilege escalation and denial of service techniques where improper input validation leads to kernel memory corruption.
The mitigation strategy involves correcting the error checking logic by replacing IS_ERR() usage with appropriate NULL pointer checks when dealing with functions that return pointers rather than error codes. This aligns with CWE-476 which addresses null pointer dereference issues, specifically targeting improper handling of return values from kernel functions. The fix requires updating the drm/imagination driver code to properly validate pvr_vm_context_lookup() return values by checking for NULL instead of using IS_ERR(), ensuring that all pointer validation paths correctly handle both valid pointer and NULL return scenarios. Additionally, implementing proper input sanitization at the ioctl interface level would further strengthen defenses against malformed VM context handles from userspace applications.