CVE-2026-53402 — fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

When fbcon_do_set_font() fails (e.g., due to a memory allocation failure inside vc_resize() under heavy memory pressure), it jumps to the `err_out` label to roll back the console state. However, the current rollback logic forgets to restore the `hi_font` state, leading to a severe state machine corruption.

Earlier in the function, `set_vc_hi_font()` might be called to change `vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()` subsequently fails, the `err_out` path restores `vc_font.charcount` but entirely skips rolling back the `vc_hi_font_mask` and the screen buffer.

This mismatch leaves the terminal in a desynchronized state. Because `vc_hi_font_mask` remains set, the VT subsystem will still accept character indices greater than 255 from userspace and write them to the screen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will then use these inflated indices to access the reverted, 256-character font array, leading to a deterministic out-of-bounds read and potential kernel memory disclosure.

Fix this by adding the missing rollback logic for the `hi_font` mask and screen buffer in the error path.

USN-8726-1 — linux, linux-aws, linux-aws-7.0, linux-gcp, linux-gke, linux-hwe-7.0, linux-realtime vulnerabilities

Affected: Ubuntu:24.04:LTS: linux-aws-7.0, Ubuntu:24.04:LTS: linux-hwe-7.0, Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-gke, Ubuntu:26.04:LTS: linux-realtime

It was discovered that some Arm processors could complete a broadcast translation lookaside buffer (TLB) invalidation before memory writes made through the invalidated translation were globally observed. A local attacker could possibly use this to write to memory after permission to do so had been revoked, bypassing memory protections or escalating privileges. (CVE-2025-10263)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - User-space API (UAPI); - Kernel build system; - ARM32 architecture; - RISC-V architecture; - S390 architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - Compute Acceleration Framework; - Intel NPU Driver; - ACPI drivers; - Android drivers; - Drivers core; - Compressed RAM block device driver; - Bluetooth drivers; - Character device driver; - Hardware random number generator core; - CPU frequency scaling framework; - Hardware crypto device drivers; - Buffer Sharing and Synchronization framework; - Intel Stratix 10 firmware drivers; - FPGA Framework; - GPIO subsystem; - GPU drivers; - HID subsystem; - CoreSight HW tracing drivers; - I2C subsystem; - IIO subsystem; - IIO ADC drivers; - InfiniBand drivers; - Input Device core drivers; - Input Device (Mouse) drivers; - IOMMU subsystem; - IRQ chip drivers; - M…

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CVE-2026-53402 — fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()

USN-8726-1 — linux, linux-aws, linux-aws-7.0, linux-gcp, linux-gke, linux-hwe-7.0, linux-realtime vulnerabilities