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CVE-2026-98215

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : 7.0.4, <8c0c602202b9a4909b00bc3354e3c0355bc69e65, <=6.12.*, 6.6.144, <caa1b913d90d5dc07073733326d2af0f0288f089, 0, <7.1, 6.12.112, 6.6.158, <=6.6.*, 6.12.95, <ff20d16b2e8230c034e21540043df47222dcc09b, d844702198395d3f80222777030f69db6be6b709, bc6c380c1159de52a252ed11f19a42c47f60a735, <6.6.158, <6aaeec59aadcd1eafc18b049f1b759fb6b9d9569, cd0e707a927a70cdfd8bc5a512a9719a87f5ed51, 82544d36b1729153c8aeb179e84750f0c085d3b1, 7.2.8, <9d99b770e7b67b00bdef9005b928aad13e1d679b, 7.1, <=6.18.*, <6.18.54, <=7.2.*, 6.18.38, 8bacd09f12c27710228562e4d13163e58c5f4a45, <=*, 6.18.54, <6.12.112, 7.3

Description

In the Linux kernel, the following vulnerability has been resolved: selinux: preserve user SID across nested backing files SELinux saves the user file SID in a backing-file security blob so it remains available after mmap() replaces vma->vm_file with a backing file. For nested backing files (overlayfs over overlayfs, or FUSE passthrough backed by overlayfs), user_file may itself be a backing file. Its fsec->sid is the SID of the mounter that opened it, rather than the user that opened the top-level file. mprotect() then checks fd { use } against the mounter SID. This can incorrectly deny access without a domain transition, or check the wrong target SID after one. Copy the saved user SID when user_file is a backing file. Keep using the regular file SID for the first backing layer. With two nested overlayfs mounts and SELinux enforcing, mprotect(PROT_READ) returns EACCES with an fd { use } denial against the mounter SID. With this change, mprotect() succeeds. Tested on arm64 QEMU with a small BusyBox initramfs and a purpose-built SELinux policy. The original test was also repeated with Fedora Cloud Base 44 userspace and gave the same result.

Gravité et risque d'exploitation

CVE-2026-98215 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 0.21 %, ce qui la place devant 10.4 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions 7.0.4, <8c0c602202b9a4909b00bc3354e3c0355bc69e65, <=6.12.*, 6.6.144, <caa1b913d90d5dc07073733326d2af0f0288f089, 0, <7.1, 6.12.112, 6.6.158, <=6.6.*, 6.12.95, <ff20d16b2e8230c034e21540043df47222dcc09b, d844702198395d3f80222777030f69db6be6b709, bc6c380c1159de52a252ed11f19a42c47f60a735, <6.6.158, <6aaeec59aadcd1eafc18b049f1b759fb6b9d9569, cd0e707a927a70cdfd8bc5a512a9719a87f5ed51, 82544d36b1729153c8aeb179e84750f0c085d3b1, 7.2.8, <9d99b770e7b67b00bdef9005b928aad13e1d679b, 7.1, <=6.18.*, <6.18.54, <=7.2.*, 6.18.38, 8bacd09f12c27710228562e4d13163e58c5f4a45, <=*, 6.18.54, <6.12.112, 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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