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

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.17% · top 93% of all CVEs (14 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.

Affected products

• Linux · Linux

  • affected 868749a7456dc48e93887a8474194e2ee6d6c21f – < cb016bcb40c81e7b19c4ae6143babb366dae8e20
  • affected ebd6f886aa2447fcfcdce5450c9e1028e1d681bb – < ac562193c36696513ae196171892e9338475c4bc
  • affected a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 – < 3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5
  • affected a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 – < a7a526fbc847f07ad3a503c7382189be5ab68574
  • affected a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 – < b5bb2c696e140c399cb874def2feedf61dee27d6
  • affected a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 – < 076b1aa65f77a49bce5a48a4a55a397cfcafa2b8
  • affected a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 – < 39815715cbcfabb16fc8c5f4a23deeda20f5df62
  • affected a5a923038d70d2d4a86cb4e3f32625a5ee6e7e24 – < 8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2
  • affected f08ccb792d3eaf1dc62d8cbf6a30d6522329f660
  • affected 5.10.249 – < 5.10.261
  • affected 5.15.64 – < 5.15.212
  • affected 5.19.6 – < 5.20

• Linux · Linux

  • affected 6.0
  • unaffected < 6.0
  • unaffected 5.10.261 – ≤ 5.10.*
  • unaffected 5.15.212 – ≤ 5.15.*
  • unaffected 6.1.178 – ≤ 6.1.*
  • unaffected 6.6.145 – ≤ 6.6.*
  • unaffected 6.12.96 – ≤ 6.12.*
  • unaffected 6.18.39 – ≤ 6.18.*
  • unaffected 7.1.3 – ≤ 7.1.*
  • unaffected 7.2 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-45457 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-53402](https://cveledger.app/badge/CVE-2026-53402.svg)](https://cveledger.app/cve/CVE-2026-53402)

Record last updated 19 Oct 2026, 20:07 UTC.