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Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-64417

Linux Linux — mm: shrinker: fix NULL pointer dereference in debugfs
  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  N  N  H    5.5   .0016    4.9     —
AFFECTED
  Product  Versions                                    Fixed
  Linux    bbf535fd6f06b94b9d07ed6f09397a936d4a58d8 –  —
  Linux    6.0 –                                       6.1.178
TIMELINE
  Jul 19  Reserved by Linux
  Jul 25  Published (CNA: Linux)
  Sep 4   ENRICHED — CVE-2026-64417 (Linux). Received CVSS 5.5 and CPE data from NVD.
CWE-476 · CNA: Linux · CVSS v3.1 · 6 references · NVD status: Analyzed

Description

In the Linux kernel, the following vulnerability has been resolved: mm: shrinker: fix NULL pointer dereference in debugfs shrinker_debugfs_add() creates both "count" and "scan" debugfs files unconditionally. That assumes every shrinker implements both count_objects() and scan_objects(), which is not guaranteed. For example, the xen-backend shrinker sets count_objects() but leaves scan_objects() NULL, so writing to its scan file calls through a NULL function pointer and panics the kernel: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. Call Trace: <TASK> shrinker_debugfs_scan_write+0x12e/0x270 full_proxy_write+0x5f/0x90 vfs_write+0xde/0x420 ? filp_flush+0x75/0x90 ? filp_close+0x1d/0x30 ? do_dup2+0xb8/0x120 ksys_write+0x68/0xf0 ? filp_flush+0x75/0x90 do_syscall_64+0xb3/0x5b0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The count path has the same issue in principle if a shrinker omits count_objects(). To fix it, only create "count" and "scan" debugfs files when the corresponding callbacks are present.

Lifecycle

Complete event history — 3 events, chronological
DateEventDetail
July 19, 2026ReservedReserved by Linux
July 25, 2026PublishedPublished (CNA: Linux)
September 4, 2026ENRICHEDENRICHED — CVE-2026-64417 (Linux). Received CVSS 5.5 and CPE data from NVD.

Affected

Affected products and packages — 2 rows
VendorProduct / PackageEcosystemVersion introducedFixed
LinuxLinux—bbf535fd6f06b94b9d07ed6f09397a936d4a58d8—
LinuxLinux—6.06.1.178

Weaknesses

CWE-476

References (6)

Related

Authoritative record: CVE-2026-64417 at cve.org

Vendors: linux

Weaknesses: CWE-476

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-64417 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 Sunday, October 4, 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.