CVE-2026-98142
Vulnérabilité non évaluée dans Linux (Linux)
Description
In the Linux kernel, the following vulnerability has been resolved: drm/cirrus-qemu: Validate BAR0 size during probe The `cirrus-qemu` driver relies on `CIRRUS_VRAM_SIZE` (4 MB) to validate framebuffer sizes. However, during PCI probe, the driver mapped BAR0 without verifying that its size matches `CIRRUS_VRAM_SIZE`. If a PCI device with a BAR0 smaller than 4 MB is bound to the driver, the mapped VRAM will be smaller than expected. Because validation checks assume 4 MB VRAM, framebuffers larger than the mapped memory can be created. When the display plane is updated (e.g. during release), `cirrus_primary_plane_helper_atomic_update()` copies the framebuffer to VRAM using `drm_fb_memcpy()`. Writing past the end of the mapped I/O memory causes a supervisor write page fault: BUG: unable to handle page fault for address: ffffc9000389c000 ... RIP: 0010:memcpy_toio+0x7c/0xe0 arch/x86/lib/iomem.c:110 ... Call Trace: <TASK> iosys_map_memcpy_to include/linux/iosys-map.h:285 [inline] drm_fb_memcpy+0x325/0x5d0 drivers/gpu/drm/drm_format_helper.c:442 cirrus_primary_plane_helper_atomic_update+0x98a/0xb00 drivers/gpu/drm/tiny/cirrus-qemu.c:358 drm_atomic_helper_commit_planes+0x626/0xea0 drivers/gpu/drm/drm_atomic_helper.c:3038 drm_atomic_helper_commit_tail+0x60/0x510 drivers/gpu/drm/drm_atomic_helper.c:1989 commit_tail+0x2b1/0x3c0 drivers/gpu/drm/drm_atomic_helper.c:2074 drm_atomic_helper_commit+0xa77/0xb10 drivers/gpu/drm/drm_atomic_helper.c:2312 Fix this by validating in `cirrus_pci_probe()` that the PCI BAR0 resource is not less than `CIRRUS_VRAM_SIZE`, returning `-ENODEV` if it is less.
Gravité et risque d'exploitation
CVE-2026-98142 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 0.16 %, ce qui la place devant 4.3 % des CVE référencées.
Que faire ?
- Vérifiez si Linux (versions <=6.12.*, 7.2.7, 5.2, 6.18.53, 0, <26bd90c886218f36c9adeab206b0e27b4384e2f6, 6.6.158, <=6.6.*, ab3e023b1b4c9887c9f0f761b47f3f0516bd3434, <=6.18.*, <0b5084a1f070ad1fc34e11945644ae034bbc774c, <=7.2.*, <2a0e7bcff3fa63e7309d2b39e18af59eb8ef2b6e, <=*, <144f51cd0ccc3ad47a6099917b7bb535611fb18f, <92312d333bf700798f92f30406c721bce87506f3, <5.2, 6.12.111, 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
- https://git.kernel.org/stable/c/2a0e7bcff3fa63e7309d2b39e18af59eb8ef2b6e
- https://git.kernel.org/stable/c/0b5084a1f070ad1fc34e11945644ae034bbc774c
- https://git.kernel.org/stable/c/26bd90c886218f36c9adeab206b0e27b4384e2f6
- https://git.kernel.org/stable/c/144f51cd0ccc3ad47a6099917b7bb535611fb18f
- https://git.kernel.org/stable/c/92312d333bf700798f92f30406c721bce87506f3