CVE-2026-53402: Linux kernel · Out-of-bounds Read
Source GCVE Database
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
- 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.
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
The fix involves adding rollback logic for the hi_font mask and screen buffer in the error path of fbcon_do_set_font(). Until an official patch is confirmed, avoid triggering font changes under heavy memory pressure or restrict untrusted userspace access to the VT subsystem.
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
- nvd.nist.gov/vuln/detail/CVE-2026-53402 (opens in a new tab)
- git.kernel.org/stable/c/076b1aa65f77a49bce5a48a4a55a397cfcafa2b8 (opens in a new tab)
- git.kernel.org/stable/c/39815715cbcfabb16fc8c5f4a23deeda20f5df62 (opens in a new tab)
- git.kernel.org/stable/c/8fdc8c2057eea08d40ce2c8eed41ff9e451c65c2 (opens in a new tab)
- git.kernel.org/stable/c/b5bb2c696e140c399cb874def2feedf61dee27d6 (opens in a new tab)
- git.kernel.org/stable/c/3618a4c5b2591cfa83efe74f5b18c2d02b35c3f5 (opens in a new tab)
- git.kernel.org/stable/c/a7a526fbc847f07ad3a503c7382189be5ab68574 (opens in a new tab)
- git.kernel.org/stable/c/ac562193c36696513ae196171892e9338475c4bc (opens in a new tab)
- git.kernel.org/stable/c/cb016bcb40c81e7b19c4ae6143babb366dae8e20 (opens in a new tab)