CVE-2026-89598 fbdev: ssd1307fb: defer I2C transfers from damage callbacks
A local attacker can trigger a kernel crash by causing the SSD1307 framebuffer driver to sleep while preemption is disabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89598?
CVE-2026-89598 is a denial of service vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
fbdev: ssd1307fb: defer I2C transfers from damage callbacks
The fbdev damage callbacks may run from fbcon while printk has disabled preemption. They currently update the display synchronously, which enters the sleeping I2C transfer path from atomic context.
A complete report from an RK3566 system follows:
[ 258.129004] watchdog: watchdog0: watchdog did not stop! [ 258.129067] BUG: scheduling while atomic: systemd/1/0x00000003 [ 258.129076] Modules linked in: algif_hash algif_skcipher af_alg bnep binfmt_misc lz4hc lz4 zram snd_soc_hdmi_codec brcmfmac_wcc hci_uart fb_ssd1306(C) fbtft(C) btqca btrtl btintel btsdio snd_soc_simple_card motorcomm pwm_fan snd_soc_simple_card_utils ssd130x_spi nls_iso8859_1 ssd130x btbcm drm_shmem_helper display_connector brcmfmac ssd1307fb brcmutil bluetooth cfg80211 rfkill snd_soc_rockchip_i2s_tdm snd_soc_rk817 hantro_vpu snd_soc_core snd_compress snd_pcm_dmaengine v4l2_vp9 snd_pcm v4l2_h264 rockchip_rga snd_timer rk_crypto2 spi_rockchip_sfc videobuf2_dma_contig snd sm3_generic v4l2_mem2mem videobuf2_dma_sg dwmac_rk sm3 soundcore videobuf2_memops videobuf2_v4l2 stmmac_platform dw_hdmi_cec videodev videobuf2_common dw_hdmi_i2s_audio stmmac rk817_charger pcs_xpcs mc cpufreq_dt sch_fq_codel ip_tables x_tables autofs4 [ 258.129215] Preemption disabled at: [ 258.129216] [<ffff80008012f96c>] vprintk_emit+0x11c/0x340 [ 258.129234] CPU: 0 PID: 1 Comm: systemd Tainted: G C 6.6.0-rc5-rockchip-rk356x #4 [ 258.129239] Hardware name: Rockchip RK3566 OPi 3B (DT) [ 258.129243] Call trace: [ 258.129245] dump_backtrace+0xa0/0x128 [ 258.129252] show_stack+0x20/0x38 [ 258.129256] dump_stack_lvl+0x60/0xb0 [ 258.129265] dump_stack+0x18/0x28 [ 258.129269] __schedule_bug+0xa0/0xc8 [ 258.129274] __schedule+0x9ac/0xd30 [ 258.129279] schedule+0x60/0x100 [ 258.129282] schedule_timeout+0x194/0x338 [ 258.129289] rk3x_i2c_xfer_common.isra.0+0x384/0x498 [ 258.129296] rk3x_i2c_xfer+0x20/0x60 [ 258.129300] __i2c_transfer+0x194/0x648 [ 258.129308] i2c_transfer+0x9c/0x130 [ 258.129313] i2c_transfer_buffer_flags+0x64/0x98 [ 258.129318] ssd1307fb_update_rect+0x42c/0x560 [ssd1307fb] [ 258.129334] ssd1307fb_defio_imageblit+0x34/0x50 [ssd1307fb] [ 258.129343] soft_cursor+0x13c/0x210 [ 258.129350] bit_cursor+0x2dc/0x550 [ 258.129354] fbcon_cursor+0xec/0x108 [ 258.129359] hide_cursor+0x44/0xc8 [ 258.129365] vt_console_print+0x398/0x3b0 [ 258.129370] console_flush_all.isra.0+0x17c/0x410 [ 258.129377] console_unlock+0x4c/0x100 [ 258.129382] vprintk_emit+0x1c8/0x340 [ 258.129386] vprintk_default+0x40/0x58 [ 258.129389] vprintk+0xb8/0xd0 [ 258.129392] _printk+0x68/0x98 [ 258.129398] watchdog_release+0x170/0x230 [ 258.129404] __fput+0xbc/0x288 [ 258.129409] __fput_sync+0x58/0x70 [ 258.129413] __arm64_sys_close+0x40/0x90 [ 258.129419] invoke_syscall+0x4c/0x118 [ 258.129426] el0_svc_common.constprop.0+0x48/0xf0 [ 258.129432] do_el0_svc+0x24/0x38 [ 258.129437] el0_svc+0x48/0x100 [ 258.129443] el0t_64_sync_handler+0xc0/0xc8 [ 258.129448] el0t_64_sync+0x190/0x198 [ 258.573087] ------------[ cut here ]------------ [ 258.573098] DEBUG_LOCKS_WARN_ON(val > preempt_count()) [ 258.573111] WARNING: CPU: 0 PID: 1 at kernel/sched/core.c:5871 preempt_count_sub+0x9c/0x148 [ 258.573130] Modules linked in: algif_hash algif_skcipher af_alg bnep binfmt_misc lz4hc lz4 zram snd_soc_hdmi_codec brcmfmac_wcc hci_uart fb_ssd1306(C) fbtft(C) btqca btrtl btintel btsdio snd_soc_simple_card motorcomm pwm_fan snd_soc_simple_card_utils ssd130x_spi nls_iso8859_1 ssd130x btbcm drm_shmem_helper display_connector brcmfmac ssd1307fb brcmutil bluetooth cfg80211 rfkill snd_soc_rockchip_i2s_tdm snd_soc_rk817 hantro_vpu snd_soc_core snd_compress snd_pcm_dmaengine v4l2_vp ---truncated---
Which versions are affected by CVE-2026-89598?
How do I fix CVE-2026-89598?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-89598 being exploited?
There is no known exploitation of CVE-2026-89598 in the wild and no public exploit code.
Sources
Also known as AZL-100193, BELL-CVE-2026-89598, DEBIAN-CVE-2026-89598, GHSA-xvg2-4qx6-6h6p, UBUNTU-CVE-2026-89598.