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CVE-2026-98840

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : <5.11, <=6.12.*, 6.6.144, <6.12.113, 5.15.211, 7.0.14, 0, a287620312dc6dcb9a093417a0e589bf30fcf38a, 7.2.10, 74be188eb2dc1c99d63986167b9a67d415fe7326, <7.1, 43a6281790273c1b0a9ab76609ff0245b968f1e6, 5.10.260, ff4806202749a51938236214adc0281481a57366, 6.12.95, <1485a3dd97ab1af2605243cabe6b604546d46dd1, 8232fca738011ca2ec865b46ec721d1796dc0580, <6.18.56, 7.1.2, 6.18.37, <5.16, <=6.18.*, <6.2, 6.1.177, b6bbb85cf45bf0b070e741997fe0af3a772c5ad5, <=7.2.*, <6.7, 09a43e81279b8da15526da09877134b8bcf618b0, 6.12.113, <9dfcadc5e003fb250dd471db90144bd5366140e9, <=*, <226bd5603371cd9f6642cbb9e9a677f445de3530, 6.18.56, 73049768ad57145acd337102c5aa3c788e6642c8, 7cc3dd79777f6ae4625ec37e84dd18a26dc88bde, <7.2, <233a2e190b12884d186027d0b86d43a48799b69c, 7.2, 7.3

Description

In the Linux kernel, the following vulnerability has been resolved: vc_screen: reload vc pointer before if (ret) in vcs_write() to avoid UAF The reload of 'vc' added by commit 8fb9ea65c9d1 ("vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF") sits after the 'if (ret)' block, so the copy-failure break path exits the loop without reloading vc. If the vc was kfree()'d via vc_port_destruct during the unlocked copy_from_user() window, the post-loop 'if (written && vc) vcs_scr_updated(vc)' is reached with a stale non-NULL vc. The '&& vc' guard from commit a287620312dc ("vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_write") only handles the NULL case, not this stale-non-NULL case; vcs_notifier() then reads param->vc->vc_num from freed memory: BUG: KASAN: slab-use-after-free in vcs_notifier+0x7c/0xd0 Read of size 2 at addr ffff888007149190 Call Trace: vcs_notifier+0x7c/0xd0 atomic_notifier_call_chain+0x70/0xa0 vcs_scr_updated+0x77/0xa0 vcs_write+0x71b/0x7e0 Allocated by task: vc_allocate -> con_install -> tty_open Freed by task: kfree <- vt_ioctl (VT_DISALLOCATE -> vc_port_destruct) Move the reload to immediately after console_lock(), before 'if (ret)', so every break path below passes a fresh vc to the post-loop vcs_scr_updated().

Gravité et risque d'exploitation

CVE-2026-98840 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 0.17 %, ce qui la place devant 5.7 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <5.11, <=6.12.*, 6.6.144, <6.12.113, 5.15.211, 7.0.14, 0, a287620312dc6dcb9a093417a0e589bf30fcf38a, 7.2.10, 74be188eb2dc1c99d63986167b9a67d415fe7326, <7.1, 43a6281790273c1b0a9ab76609ff0245b968f1e6, 5.10.260, ff4806202749a51938236214adc0281481a57366, 6.12.95, <1485a3dd97ab1af2605243cabe6b604546d46dd1, 8232fca738011ca2ec865b46ec721d1796dc0580, <6.18.56, 7.1.2, 6.18.37, <5.16, <=6.18.*, <6.2, 6.1.177, b6bbb85cf45bf0b070e741997fe0af3a772c5ad5, <=7.2.*, <6.7, 09a43e81279b8da15526da09877134b8bcf618b0, 6.12.113, <9dfcadc5e003fb250dd471db90144bd5366140e9, <=*, <226bd5603371cd9f6642cbb9e9a677f445de3530, 6.18.56, 73049768ad57145acd337102c5aa3c788e6642c8, 7cc3dd79777f6ae4625ec37e84dd18a26dc88bde, <7.2, <233a2e190b12884d186027d0b86d43a48799b69c, 7.2, 7.3) 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

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