CVE-2024-35932

What it is

In the Linux kernel, the following vulnerability has been resolved: drm/vc4: don't check if plane->state->fb == state->fb Currently, when using non-blocking commits, we can see the following kernel warning: [ 110.908514] ------------[ cut here ]------------ [ 110.908529] refcount_t: underflow; use-after-free. [ 110.908620] WARNING: CPU: 0 PID: 1866 at lib/refcount.c:87 refcount_dec_not_one+0xb8/0xc0 [ 110.908664] Modules linked in: rfcomm snd_seq_dummy snd_hrtimer snd_seq snd_seq_device cmac algif_hash aes_arm64 aes_generic algif_skcipher af_alg bnep hid_logitech_hidpp vc4 brcmfmac hci_uart btbcm brcmutil bluetooth snd_soc_hdmi_codec cfg80211 cec drm_display_helper drm_dma_helper drm_kms_helper snd_soc_core snd_compress snd_pcm_dmaengine fb_sys_fops sysimgblt syscopyarea sysfillrect raspberrypi_hwmon ecdh_generic ecc rfkill libaes i2c_bcm2835 binfmt_misc joydev snd_bcm2835(C) bcm2835_codec(C) bcm2835_isp(C) v4l2_mem2mem videobuf2_dma_contig snd_pcm bcm2835_v4l2(C) raspberrypi_gpiomem bcm2835_mmal_vchiq(C) videobuf2_v4l2 snd_timer videobuf2_vmalloc videobuf2_memops videobuf2_common snd videodev vc_sm_cma(C) mc hid_logitech_dj uio_pdrv_genirq uio i2c_dev drm fuse dm_mod drm_panel_orientation_quirks backlight ip_tables x_tables ipv6 [ 110.909086] CPU: 0 PID: 1866 Comm: kodi.bin Tainted: G C 6.1.66-v8+ #32 [ 110.909104] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT) [ 110.909114] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 110.909132] pc : refcount_dec_not_one+0xb8/0xc0 [ 110.909152] lr : refcount_dec_not_one+0xb4/0xc0 [ 110.909170] sp : ffffffc00913b9c0 [ 110.909177] x29: ffffffc00913b9c0 x28: 000000556969bbb0 x27: 000000556990df60 [ 110.909205] x26: 0000000000000002 x25: 0000000000000004 x24: ffffff8004448480 [ 110.909230] x23: ffffff800570b500 x22: ffffff802e03a7bc x21: ffffffecfca68c78 [ 110.909257] x20: ffffff8002b42000 x19: ffffff802e03a600 x18: 0000000000000000 [ 110.909283] x17: 0000000000000011 x16: ffffffffffffffff x15: 0000000000000004 [ 110.909308] x14: 0000000000000fff x13: ffffffed577e47e0 x12: 0000000000000003 [ 110.909333] x11: 0000000000000000 x10: 0000000000000027 x9 : c912d0d083728c00 [ 110.909359] x8 : c912d0d083728c00 x7 : 65646e75203a745f x6 : 746e756f63666572 [ 110.909384] x5 : ffffffed579f62ee x4 : ffffffed579eb01e x3 : 0000000000000000 [ 110.909409] x2 : 0000000000000000 x1 : ffffffc00913b750 x0 : 0000000000000001 [ 110.909434] Call trace: [ 110.909441] refcount_dec_not_one+0xb8/0xc0 [ 110.909461] vc4_bo_dec_usecnt+0x4c/0x1b0 [vc4] [ 110.909903] vc4_cleanup_fb+0x44/0x50 [vc4] [ 110.910315] drm_atomic_helper_cleanup_planes+0x88/0xa4 [drm_kms_helper] [ 110.910669] vc4_atomic_commit_tail+0x390/0x9dc [vc4] [ 110.911079] commit_tail+0xb0/0x164 [drm_kms_helper] [ 110.911397] drm_atomic_helper_commit+0x1d0/0x1f0 [drm_kms_helper] [ 110.911716] drm_atomic_commit+0xb0/0xdc [drm] [ 110.912569] drm_mode_atomic_ioctl+0x348/0x4b8 [drm] [ 110.913330] drm_ioctl_kernel+0xec/0x15c [drm] [ 110.914091] drm_ioctl+0x24c/0x3b0 [drm] [ 110.914850] __arm64_sys_ioctl+0x9c/0xd4 [ 110.914873] invoke_syscall+0x4c/0x114 [ 110.914897] el0_svc_common+0xd0/0x118 [ 110.914917] do_el0_svc+0x38/0xd0 [ 110.914936] el0_svc+0x30/0x8c [ 110.914958] el0t_64_sync_handler+0x84/0xf0 [ 110.914979] el0t_64_sync+0x18c/0x190 [ 110.914996] ---[ end trace 0000000000000000 ]--- This happens because, although `prepare_fb` and `cleanup_fb` are perfectly balanced, we cannot guarantee consistency in the check plane->state->fb == state->fb. This means that sometimes we can increase the refcount in `prepare_fb` and don't decrease it in `cleanup_fb`. The opposite can also be true. In fact, the struct drm_plane .state shouldn't be accessed directly but instead, the `drm_atomic_get_new_plane_state()` helper function should be used. So, we could stick to this check, but using `drm_atomic_get_new_plane_state()`. But actually, this check is not re ---truncated---

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2024-05-19 11:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-04 11:18 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 7.8 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2024-05-19 11:15 UTC

Last modified

2026-08-04 11:18 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-416 · Use after free

Record status

Modified

Affected

• Linux Kernel < 6.1.86
• Linux Kernel < 6.6.27
• Linux Kernel < 6.8.6

Attack profile CVSS 3.1 · 7.8

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2024-35932.md and follow it. Check whether this project is affected by CVE-2024-35932. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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