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CVE-2026-64317

Vulnérabilité élevée dans Linux (Linux)

CVSS 7.1 · Élevée
EPSS 0.2%
Linux•Linux•Versions : <=6.1.*, <=6.12.*, <9830725078c8483c6831ec10222ae724806ea36b, 2.6.12, 6.18.39, <a22cb6bb54dc167047ea9e70d97dfbc2c15649e3, <b5699642640d6cff357638738c5293985cd5a53d, 0, <36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee, <=7.1.*, 7.1.4, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <b736b12108fd116c41777628f5a333791604df26, 6.1.178, <=5.10.*, <=6.6.*, <=6.18.*, 5.15.212, 6.6.145, 5.10.261, <5fa1d6a5ec2356d2107dead614437c66fa7138b1, <=*, <1015e1c4b2fadd9c09704e24738e46598778c869, <=5.15.*, <6bf41db09ef935d76fcc84ccf213b42c18de95ee, 6.12.96, 7.2

Description

In the Linux kernel, the following vulnerability has been resolved: isofs: bound Rock Ridge symlink components to the SL record get_symlink_chunk() and the SL handling in parse_rock_ridge_inode_internal() walk the variable-length components of a Rock Ridge "SL" (symbolic link) record. Each component is a two-byte header (flags, len) followed by len bytes of text, so it occupies slp->len + 2 bytes. Both loops read slp->len and advance to the next component, and get_symlink_chunk() additionally does memcpy(rpnt, slp->text, slp->len), but neither checks that the component lies within the SL record before dereferencing it. A crafted SL record whose component declares a len that runs past the record (rr->len) therefore triggers an out-of-bounds read of up to 255 bytes. When the record sits at the tail of its backing buffer - for example a small kmalloc()ed continuation block reached through a CE record - the read crosses the allocation; get_symlink_chunk() then copies the out-of-bounds bytes into the symlink body returned to user space by readlink(), disclosing adjacent kernel memory. ISO 9660 images are routinely mounted from untrusted removable media - desktop environments auto-mount them (e.g. via udisks2) without CAP_SYS_ADMIN - so the record contents are attacker-controlled. Reject any component that does not fit in the remaining record bytes before using it. In get_symlink_chunk() return NULL, like the existing output-buffer (plimit) checks, so a malformed record makes readlink() fail with -EIO rather than silently returning a truncated target; in parse_rock_ridge_inode_internal() stop the inode-size walk.

Gravité et risque d'exploitation

CVE-2026-64317 obtient un score CVSS de 7.1/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.17 %, ce qui la place devant 6.1 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions <=6.1.*, <=6.12.*, <9830725078c8483c6831ec10222ae724806ea36b, 2.6.12, 6.18.39, <a22cb6bb54dc167047ea9e70d97dfbc2c15649e3, <b5699642640d6cff357638738c5293985cd5a53d, 0, <36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee, <=7.1.*, 7.1.4, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <b736b12108fd116c41777628f5a333791604df26, 6.1.178, <=5.10.*, <=6.6.*, <=6.18.*, 5.15.212, 6.6.145, 5.10.261, <5fa1d6a5ec2356d2107dead614437c66fa7138b1, <=*, <1015e1c4b2fadd9c09704e24738e46598778c869, <=5.15.*, <6bf41db09ef935d76fcc84ccf213b42c18de95ee, 6.12.96, 7.2) 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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