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VulnerabilityPublished Updated

CVE-2026-53402: Linux kernel · Out-of-bounds Read

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in cb016bcb40c81e7b19c4ae6143babb366dae8e20 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in cb016bcb40c81e7b19c4ae6143babb366dae8e20, b5bb2c696e140c399cb874def2feedf61dee27d6, ac562193c36696513ae196171892e9338475c4bc +8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=5.10.249 <5.10.261
  • >=5.15.64 <5.15.212
  • >=5.19.6 <5.20
Fixed in
  • cb016bcb40c81e7b19c4ae6143babb366dae8e20
  • b5bb2c696e140c399cb874def2feedf61dee27d6
  • ac562193c36696513ae196171892e9338475c4bc
  • a7a526fbc847f07ad3a503c7382189be5ab68574
  • 39815715cbcfabb16fc8c5f4a23deeda20f5df62
  • 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5
  • 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8
  • 8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2
  • 5.20
  • 5.15.212
  • 5.10.261
LinuxLinuxAffected
  • =6.0
Fixed in–

Description

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.

References

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