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CVE-2026-98214

Vulnérabilité non évaluée dans Linux (Linux)

CVSS 0.0 · Non évaluée
EPSS 0.2%
Linux•Linux•Versions : 7.0.4, <=6.12.*, 6.6.144, 0, <c2bbb905af2293549651b614a52ad91e0b462b60, <7.1, 6.12.112, 6.6.158, <=6.6.*, 6.12.95, <4d50ebe5a27724e020747ffd61a051dec67cb8ec, d844702198395d3f80222777030f69db6be6b709, bc6c380c1159de52a252ed11f19a42c47f60a735, <6.6.158, cd0e707a927a70cdfd8bc5a512a9719a87f5ed51, 82544d36b1729153c8aeb179e84750f0c085d3b1, 7.2.8, 7.1, <=6.18.*, <6.18.54, <=7.2.*, 6.18.38, 8bacd09f12c27710228562e4d13163e58c5f4a45, <d127c7e1f3e1231d8ac8b2738e3f00bea12afe74, <=*, <78fc54b934bfb2c18aad8154c7302067146946f9, 6.18.54, <89376fbfdcc1a728e1775f98752cdd90b0930a00, <6.12.112, 7.3

Description

In the Linux kernel, the following vulnerability has been resolved: selinux: recheck intermediate backing files on mprotect() mprotect() can be used to bypass the SELinux checks that mmap() performs against the intermediate layers of a stacked filesystem. mmap() checks every backing layer as the request descends through the stack. mprotect() only has the lowest backing file in vma->vm_file, so it rechecks the top-level user and the lowest mounter, but skips the mounters of every layer in between. With two nested overlayfs mounts and a policy denying mounter_t -> middle_file_t:file { execute }, a direct mmap(PROT_EXEC) is denied: avc: denied { execute } for pid=71 comm="nested_exec" path="/payload" dev="overlay" ino=9 scontext=user_u:base_r:mounter_t tcontext=user_u:object_r:middle_file_t tclass=file permissive=0 while mmap(PROT_NONE) followed by mprotect(PROT_EXEC) succeeds. Preserve each intermediate path, mounter SID and file-description SID in the backing-file security blob, copying the saved entries when another backing layer is opened. Allocate the array only for nested backing files, and release it and the path references in the backing_file_free hook. During mprotect(), recheck fd { use } and the requested inode permissions for every saved mounter, and include the intermediate layers in the execmod checks. Policy for nested stacking may then need to grant intermediate mounters what a direct mmap() already requires, and execmod on intermediate labels for binaries using text relocations. Tested on arm64 QEMU with a small BusyBox initramfs and a purpose-built SELinux policy, on a mainline tree containing commit f2381b546e7e ("fs: fix user path of nested backing files"). [PM: subject tweak]

Gravité et risque d'exploitation

CVE-2026-98214 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 0.22 %, ce qui la place devant 11.6 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions 7.0.4, <=6.12.*, 6.6.144, 0, <c2bbb905af2293549651b614a52ad91e0b462b60, <7.1, 6.12.112, 6.6.158, <=6.6.*, 6.12.95, <4d50ebe5a27724e020747ffd61a051dec67cb8ec, d844702198395d3f80222777030f69db6be6b709, bc6c380c1159de52a252ed11f19a42c47f60a735, <6.6.158, cd0e707a927a70cdfd8bc5a512a9719a87f5ed51, 82544d36b1729153c8aeb179e84750f0c085d3b1, 7.2.8, 7.1, <=6.18.*, <6.18.54, <=7.2.*, 6.18.38, 8bacd09f12c27710228562e4d13163e58c5f4a45, <d127c7e1f3e1231d8ac8b2738e3f00bea12afe74, <=*, <78fc54b934bfb2c18aad8154c7302067146946f9, 6.18.54, <89376fbfdcc1a728e1775f98752cdd90b0930a00, <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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