CVE-2026-53403: 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...

Description

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.

Metrics

EPSS Probability

0.19%

8.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 1458a4d804550b7101e8bb02c1cb941088e4c0c7; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 8707f02ac9f5f632039b60df2c9f3dc914709f72; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 0d8c7f21ad8529d5c181e61f86be35b887ae2e4d; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7640b4f68acb54c2c4f6b4a8aee0e9849dacd929; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < eea16b6f805c0b1fb2f72f0f771088ea45356956; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 88913059c77e171f44ba829282d42dde0d458811; >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 7f08fc10fa3d3366dc3af723970bd03d7d6d10e3
Linux	Linux	2.6.12

References

Timeline

Published: Jul 19, 2026
Last Modified: Jul 27, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-53403?

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.

How severe is CVE-2026-53403?

Severity scoring for CVE-2026-53403 is pending analysis. The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.

How do I fix CVE-2026-53403?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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