Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Linux Linux — iommufd: Set upper bounds on cache invalidation entry_num and entry_len
AV AC PR UI S C I A CVSS EPSS %ile KEV
L L L N U N N H 5.5 .0015 5.2 —
AFFECTED
Product Versions Fixed
Linux 8c6eabae3807e048b9f17733af5e20500fbf858c – —
Linux 6.8 – 6.12.96
TIMELINE
Jul 19 Reserved by Linux
Jul 25 Published (CNA: Linux)
Aug 17 ENRICHED — CVE-2026-64289 (Linux). Received CVSS 5.5 and CPE data from NVD.
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| July 19, 2026 | Reserved | Reserved by Linux |
| July 25, 2026 | Published | Published (CNA: Linux) |
| August 17, 2026 | ENRICHED | ENRICHED — CVE-2026-64289 (Linux). Received CVSS 5.5 and CPE data from NVD. |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | 8c6eabae3807e048b9f17733af5e20500fbf858c | — |
| Linux | Linux | — | 6.8 | 6.12.96 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-64289 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.