Out-of-bounds Read Affecting kernel-default-livepatch-devel package, versions <5.14.21-150500.55.182.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.14% (4th percentile)

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  • Snyk IDSNYK-SLES155-KERNELDEFAULTLIVEPATCHDEVEL-18750886
  • published13 Aug 2026
  • disclosed12 Aug 2026

Introduced: 12 Aug 2026

NewCVE-2026-53402  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade SLES:15.5 kernel-default-livepatch-devel to version 5.14.21-150500.55.182.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch-devel package and not the kernel-default-livepatch-devel package as distributed by SLES. See How to fix? for SLES:15.5 relevant fixed versions and status.

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-&gt;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.

CVSS Base Scores

version 3.1