CVE-2026-64289
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 versions
Linux kernel versions
6.8
and later are affected. Fixed in
6.12.96,
6.18.39,
7.1.4,
7.2-rc1
and their respective stable series.
References
4 totalFrequently asked questions
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What is CVE-2026-64289?
CVE-2026-64289 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.8 onward and has been patched in 6.12.96, 6.18.39, 7.1.4 and others. CVE-2026-64289 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-64289?
Yes. CVE-2026-64289 has been patched. Fixed versions include 6.12.96, 6.18.39, 7.1.4 and others. If you are running Linux kernel 6.8 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-64289 actively exploited?
No. CVE-2026-64289 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.