fbdev: Fix fb_new_modelist to prevent null-ptr-deref in fb_videomode_to_var
Published Jul 19, 2026
5.5
MEDIUMCVSS 3.1
EPSS 0.13%
Description
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.
Affected products
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- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version
-
- Version 2.6.12StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<2.6.12
- Version 5.10.260StatusunaffectedConstraints<=5.10.*
- Version 5.15.211StatusunaffectedConstraints<=5.15.*
- Version 6.1.177StatusunaffectedConstraints<=6.1.*
- Version 6.12.95StatusunaffectedConstraints<=6.12.*
- Version 6.18.38StatusunaffectedConstraints<=6.18.*
- Version 6.6.144StatusunaffectedConstraints<=6.6.*
- Version 7.1.3StatusunaffectedConstraints<=7.1.*
- Version 7.2StatusunaffectedConstraints<=*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
| |||||||||||||||||||||||||||||||||
| Linux | Linux | 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
- 2.6.12
- 2.6.12
- 2.6.12
- 2.6.12
No data.
Red Hat Enterprise Linux 10
kernel
Fix deferred
Red Hat Enterprise Linux 6
kernel
Not affected
Red Hat Enterprise Linux 7
kernel
Not affected
Red Hat Enterprise Linux 7
kernel-rt
Not affected
Red Hat Enterprise Linux 8
kernel
Fix deferred
Red Hat Enterprise Linux 8
kernel-rt
Fix deferred
Red Hat Enterprise Linux 9
kernel
Fix deferred
Red Hat Enterprise Linux 9
kernel-rt
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 6 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | n/a |
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (14)
- https://access.redhat.com/security/cve/CVE-2026-53403 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2502208 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-45458 Advisory
- https://git.kernel.org/stable/c/0d8c7f21ad8529d5c181e61f86be35b887ae2e4d Patch
- https://git.kernel.org/stable/c/1458a4d804550b7101e8bb02c1cb941088e4c0c7 Patch
- https://git.kernel.org/stable/c/4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e Patch
- https://git.kernel.org/stable/c/7640b4f68acb54c2c4f6b4a8aee0e9849dacd929 Patch
- https://git.kernel.org/stable/c/7f08fc10fa3d3366dc3af723970bd03d7d6d10e3 Patch
- https://git.kernel.org/stable/c/8707f02ac9f5f632039b60df2c9f3dc914709f72 Patch
- https://git.kernel.org/stable/c/88913059c77e171f44ba829282d42dde0d458811 Patch
- https://git.kernel.org/stable/c/eea16b6f805c0b1fb2f72f0f771088ea45356956 Patch
- https://lore.kernel.org/linux-cve-announce/2026071959-CVE-2026-53403-6dc1@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2026-53403
- https://www.cve.org/CVERecord?id=CVE-2026-53403
Change history (0)
No recorded changes yet.