CVE-2026-53403

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.

Gravité et risque d'exploitation

CVE-2026-53403 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.13 %, ce qui la place devant 2.3 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <eea16b6f805c0b1fb2f72f0f771088ea45356956, 7.2, <=6.12.*, 6.6.144, 2.6.12, 5.15.211, <8707f02ac9f5f632039b60df2c9f3dc914709f72, 0, <88913059c77e171f44ba829282d42dde0d458811, <=7.1.*, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 5.10.260, <7f08fc10fa3d3366dc3af723970bd03d7d6d10e3, <=5.10.*, <=6.6.*, 6.12.95, <=6.18.*, <7640b4f68acb54c2c4f6b4a8aee0e9849dacd929, 6.1.177, 6.18.38, <4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e, <=*, <=5.15.*, 7.1.3, <1458a4d804550b7101e8bb02c1cb941088e4c0c7, <0d8c7f21ad8529d5c181e61f86be35b887ae2e4d) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/1458a4d804550b7101e8bb02c1cb941088e4c0c7
• https://git.kernel.org/stable/c/8707f02ac9f5f632039b60df2c9f3dc914709f72
• https://git.kernel.org/stable/c/0d8c7f21ad8529d5c181e61f86be35b887ae2e4d
• https://git.kernel.org/stable/c/7640b4f68acb54c2c4f6b4a8aee0e9849dacd929
• https://git.kernel.org/stable/c/4f1a7fe8ba845cb7d39580755f78c3b7b9a0b61e
• https://git.kernel.org/stable/c/eea16b6f805c0b1fb2f72f0f771088ea45356956
• https://git.kernel.org/stable/c/88913059c77e171f44ba829282d42dde0d458811
• https://git.kernel.org/stable/c/7f08fc10fa3d3366dc3af723970bd03d7d6d10e3