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Linux KernelOperating system · Linux

CVE-2026-53403

MEDIUM · 5.5 CVSS v3.1 Published 2026-07-19
Fix available
A fix is available. Upgrade to 5.10.260 / 5.15.211 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click 4 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var info->var, a framebuffer's current mode, is expected to have a matching entry in info->modelist. var_to_display() relies on this and treats a failed fb_match_mode() as "This should not happen". fb_set_var() keeps it true by adding the mode to the list on every change, and do_register_framebuffer() does the same at registration. store_modes() replaces the modelist from userspace. fb_new_modelist() validates the new modes but does not check that info->var still has a match. It relies on fbcon_new_modelist() to re-point consoles, but that only handles consoles mapped to the framebuffer. With fbcon unbound there are none, so info->var is left describing a mode that is no longer in the list. A later console takeover runs var_to_display(), where fb_match_mode() returns NULL and leaves fb_display[i].mode NULL. fbcon_switch() passes it to display_to_var(), and fb_videomode_to_var() dereferences the NULL mode. Keep the current mode in the list in fb_new_modelist(), the same way fb_set_var() does.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.12.1, < 5.10.260>= 5.11, < 5.15.211>= 5.16, < 6.1.177>= 6.2, < 6.6.144>= 6.7, < 6.12.95>= 6.13, < 6.18.38>= 6.19, < 7.1.3= 2.6.12

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.260 / 5.15.211 / 6.1.177 or later
Fixed in 5.10.2605.15.2116.1.177
Recommended fix High confidence

Upgrade to one of: 6.6.144 (if on 6.2+), 6.1.177 (if on 5.16-6.1), 5.15.211 (if on 5.11-5.15), or 5.10.260 (if on < 5.10)

  1. Identify current kernel version using `uname -r`
  2. Determine which version range your current kernel falls into from: 5.10.x, 5.11-5.15.x, 5.16-6.1.x, or 6.2-6.6.x
  3. For kernels < 5.10.260: upgrade to 5.10.260 or later
  4. For kernels >= 5.11 and < 5.15.211: upgrade to 5.15.211 or later
  5. For kernels >= 5.16 and < 6.1.177: upgrade to 6.1.177 or later
  6. For kernels >= 6.2 and < 6.6.144: upgrade to 6.6.144 or later
  7. After upgrade, verify kernel version with `uname -r`
  8. Reboot the system to load the new kernel
Caveat Major kernel upgrades may require rebuilding out-of-tree kernel modules; ensure compatibility of hardware drivers and critical software with the new kernel version before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53403 in production — separate from our analysis above.

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What this is

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  • Version or environment caveats, and links to real fixes
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