Skip to content
CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-64289

iommufd: Set upper bounds on cache invalidation entry_num and entry_len

Description

In the Linux kernel, the following vulnerability has been resolved: iommufd: Set upper bounds on cache invalidation entry_num and entry_len iommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len, each bounded only by U32_MAX. An entry_len beyond the kernel's struct size makes the copy helper verify the extra bytes are zero, scanning that excess in one uninterruptible pass; a multi-gigabyte value over zeroed user memory trips the soft-lockup watchdog. A large entry_num is the other half, driving the backend invalidation loop with no reschedule. The VT-d nested handler, for one, copies each entry and flushes caches per iteration, pinning the CPU on a non-preemptible kernel. Cap both in the ioctl. entry_len is held under PAGE_SIZE, above any request struct, and entry_num under 1 << 19, the order of a hardware invalidation queue and well beyond any real batch, bounding the per-call loop length.

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

  • 8c6eabae3807e048b9f17733af5e20500fbf858c to < d2bd041e0efaf7d81789779b135279d18b33d6d5affected
  • 8c6eabae3807e048b9f17733af5e20500fbf858c to < 32ca4aed2a66205b072fcfecabe220289a8149ffaffected
  • 8c6eabae3807e048b9f17733af5e20500fbf858c to < 2c6381d90898089287e0a358f06f89f6b4b389f2affected
  • 8c6eabae3807e048b9f17733af5e20500fbf858c to < 4d70986002f2f3eaaed89124fb2522bded38b016affected

Linux Linux

Default version status: affected

  • 6.8affected
  • 0 to < 6.8unaffected
  • 6.12.96 to ≤ 6.12.*unaffected
  • 6.18.39 to ≤ 6.18.*unaffected
  • 7.1.4 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References