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Fencer Vulns
high 7.8

CVE-2026-64300 json

perf/aux: Fix page UAF in map_range()

published 2026-07-25 3 mo ago modified 2026-09-03 2 mo ago also EUVD-2026-49012

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

perf/aux: Fix page UAF in map_range()

map_range() reads rb->aux_pages[], rb->aux_nr_pages and rb->aux_pgoff via perf_mmap_to_page() while holding only event->mmap_mutex. Those fields are serialized by rb->aux_mutex, and mmap_mutex is per event.

Thus, two events sharing one rb via PERF_EVENT_IOC_SET_OUTPUT can race rb_alloc_aux() with map_range(), leading to a page-UAF scenario as follows:

CPU 0 CPU 1 ===== ===== rb_alloc_aux() map_range() [1]: allocate rb->aux_pages[0] [2]: rb->aux_nr_pages++ [3]: perf_mmap_to_page() returns rb->aux_pages[0] [4]: map it as VM_PFNMAP [5]: rb->aux_pgoff = 1

munmap the page [6]: free rb->aux_pages[0]

Pages mapped as VM_PFNMAP have no refcount protection, so CPU 1 holds a mapping to a freed physical frame.

Fix this by taking rb->aux_mutex across the page walk in map_range().

Patch / fix

  • Linux Linux 6.18.39, 7.1.4, 7.2
  • linux Debian 14 7.1.4-1

debian advisories DEBIAN-CVE-2026-64300

  • linux Ubuntu 26.04 LTS 7.0.0-31.31
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1011.11
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1006.7
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1013.13
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-raspi Ubuntu 26.04 LTS 7.0.0-1019.19
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-31.31.1

ubuntu advisories UBUNTU-CVE-2026-64300

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.2 6.12.0-211.47.1.el10_2
  • rv RHEL 10.2 6.12.0-211.47.1.el10_2
  • perf RHEL 10.2 6.12.0-211.47.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.47.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.47.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.47.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.47.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.47.1.el10_2

red hat advisories RHSA-2026:54343

  • kernel-rt Linux Micro 6.2 6.12.0-160000.38.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.38.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1.160000.2.23
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.38.1
  • kernel-azure SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.38.1

suse advisories SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1openSUSE-SU-2026:11476-1

  • kernel AlmaLinux 10 6.12.0-211.47.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.47.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.47.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.47.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.47.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.47.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.47.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.47.1.el10_2

almalinux advisories ALSA-2026:54343

  • kernel Rocky Linux 10 6.12.0-211.47.1.el10_2

rocky linux advisories RLSA-2026:54343

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-64300 updated cvss 7.0

kernel: perf/aux: Fix page UAF in map_range()

  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.47.1.el10_2, perf 6.12.0-211.47.1.el10_2, rtla 6.12.0-211.47.1.el10_2, python3-perf 6.12.0-211.47.1.el10_2, kernel-devel-matched 6.12.0-211.47.1.el10_2, kernel-64k-devel-matched 6.12.0-211.47.1.el10_2, +7 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.47.1.el10_2, kernel-64k 6.12.0-211.47.1.el10_2, kernel-core 6.12.0-211.47.1.el10_2, kernel-tools 6.12.0-211.47.1.el10_2, kernel-modules 6.12.0-211.47.1.el10_2, kernel-64k-core 6.12.0-211.47.1.el10_2, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.47.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.47.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.47.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.47.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.47.1.el10_2 Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.47.1.el10_2, kernel-rt-64k 6.12.0-211.47.1.el10_2, kernel-rt-core 6.12.0-211.47.1.el10_2, kernel-rt-modules 6.12.0-211.47.1.el10_2, kernel-rt-64k-core 6.12.0-211.47.1.el10_2, kernel-rt-debug-core 6.12.0-211.47.1.el10_2, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.47.1.el10_2, kernel-rt-core 6.12.0-211.47.1.el10_2, kernel-rt-modules 6.12.0-211.47.1.el10_2, kernel-rt-debug-core 6.12.0-211.47.1.el10_2, kernel-rt-modules-core 6.12.0-211.47.1.el10_2, kernel-rt-debug-modules 6.12.0-211.47.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:54343
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

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