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CVE PROGRAM SOURCE RECORD7.0 High

CVE-2026-97926

ufs: validate cylinder group metadata before caching it

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ufs: validate cylinder group metadata before caching it ufs_read_cylinder() copies the cylinder group index and the rotor positions straight from the on-disk group and caches them without any check: ucpi->c_cgx = fs32_to_cpu(sb, ucg->cg_cgx); ucpi->c_rotor = fs32_to_cpu(sb, ucg->cg_rotor); ucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor); ucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor); They are then used as indices during allocation and free: - c_cgx indexes the cylinder summary array as UFS_SB(sb)->fs_cs(ucpi->c_cgx), so a value past s_ncg writes a 32 bit count outside the s_csp allocation. - c_frotor becomes a bitmap scan start, start = c_frotor >> 3, and then length = ((s_fpg + 7) >> 3) - start. A start beyond the block bitmap wraps the unsigned length to a huge value, so ubh_scanc() walks far past the cylinder group buffers. c_irotor drives the inode bitmap the same way. A crafted image can set any of these freely, turning an ordinary allocation into an out of bounds access. Reject a cylinder group whose recorded index does not match the group being read, or whose rotors fall outside the group, before the metadata is cached. Valid filesystems keep cg_cgx equal to the group number and the rotors within the group, so only malformed images are rejected.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 88cccb6beba136b73f0caf80e59457e1b3c0ca1eaffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < f560a9e33365c460827c735fd86435f9213f1aedaffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < e4c5cc9688c3e69d07d888853388549ae26c0521affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 58c0c414b2b8d099d33da494a354fa836ca6c10baffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 5902a95066883cf96fa15b2680694fc5dd0c7d11affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 87b12dc360a002eb2d498aa4f01e84347019612daffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < abde9eb33106850dfa367ad3965d3588bb8558d5affected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < c9d263be26806d388129fab8c6904bed197fc6afaffected

Linux Linux

Default version status: affected

  • 2.6.12affected
  • 0 to < 2.6.12unaffected
  • 5.10.271 to ≤ 5.10.*unaffected
  • 5.15.222 to ≤ 5.15.*unaffected
  • 6.1.189 to ≤ 6.1.*unaffected
  • 6.6.158 to ≤ 6.6.*unaffected
  • 6.12.111 to ≤ 6.12.*unaffected
  • 6.18.53 to ≤ 6.18.*unaffected
  • 7.2.7 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References