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Fencer Vulns
high 7.8

CVE-2026-72080 json

fs/resctrl: Fix use-after-free during unmount

published 2026-08-15 2 mo ago modified 2026-10-19 20 d ago also EUVD-2026-59038

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 6%
public exploits
0
none known

Summary

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

fs/resctrl: Fix use-after-free during unmount

During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group.

A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader.

When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data.

The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv;

/* md points to freed mon_data */

Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group.

Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed.

Patch / fix

  • Linux Linux 6.18.42, 7.1.5, 7.2
  • linux Debian 14 7.1.5-1

debian advisories DEBIAN-CVE-2026-72080

  • linux Ubuntu 26.04 LTS 7.0.0-38.38
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-gke Ubuntu 26.04 LTS 7.0.0-1008.9
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1015.15
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-38.38.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1013.13

ubuntu advisories UBUNTU-CVE-2026-72080

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 AlmaLinux 9 5.14.0-687.66.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.66.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.66.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.66.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.66.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.66.1.el9_8

almalinux advisories ALSA-2026:95370ALSA-2026:95367

  • kernel Rocky Linux 10 6.12.0-211.74.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.66.1.el9_8

rocky linux advisories RLSA-2026:95367RLSA-2026:95370

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-2026-72080 updated cvss 4.7

kernel: fs/resctrl: Fix use-after-free during unmount

  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.66.1.el9_8, perf 5.14.0-687.66.1.el9_8, rtla 5.14.0-687.66.1.el9_8, python3-perf 5.14.0-687.66.1.el9_8, kernel-devel-matched 5.14.0-687.66.1.el9_8, kernel-64k-devel-matched 5.14.0-687.66.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.74.1.el10_2, perf 6.12.0-211.74.1.el10_2, rtla 6.12.0-211.74.1.el10_2, python3-perf 6.12.0-211.74.1.el10_2, kernel-devel-matched 6.12.0-211.74.1.el10_2, kernel-64k-devel-matched 6.12.0-211.74.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.66.1.el9_8, kernel-64k 5.14.0-687.66.1.el9_8, kernel-core 5.14.0-687.66.1.el9_8, kernel-tools 5.14.0-687.66.1.el9_8, kernel-modules 5.14.0-687.66.1.el9_8, kernel-64k-core 5.14.0-687.66.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.74.1.el10_2, kernel-64k 6.12.0-211.74.1.el10_2, kernel-core 6.12.0-211.74.1.el10_2, kernel-tools 6.12.0-211.74.1.el10_2, kernel-modules 6.12.0-211.74.1.el10_2, kernel-64k-core 6.12.0-211.74.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.66.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.66.1.el9_8
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.74.1.el10_2 Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.74.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.74.1.el10_2
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.66.1.el9_8, kernel-rt-64k 5.14.0-687.66.1.el9_8, kernel-rt-core 5.14.0-687.66.1.el9_8, kernel-rt-modules 5.14.0-687.66.1.el9_8, kernel-rt-64k-core 5.14.0-687.66.1.el9_8, kernel-rt-debug-core 5.14.0-687.66.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:95370
show 4 more
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.74.1.el10_2, kernel-rt-64k 6.12.0-211.74.1.el10_2, kernel-rt-core 6.12.0-211.74.1.el10_2, kernel-rt-modules 6.12.0-211.74.1.el10_2, kernel-rt-64k-core 6.12.0-211.74.1.el10_2, kernel-rt-debug-core 6.12.0-211.74.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:95367
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.66.1.el9_8, kernel-rt-core 5.14.0-687.66.1.el9_8, kernel-rt-modules 5.14.0-687.66.1.el9_8, kernel-rt-debug-core 5.14.0-687.66.1.el9_8, kernel-rt-modules-core 5.14.0-687.66.1.el9_8, kernel-rt-debug-modules 5.14.0-687.66.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:95370
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.74.1.el10_2, kernel-rt-core 6.12.0-211.74.1.el10_2, kernel-rt-modules 6.12.0-211.74.1.el10_2, kernel-rt-debug-core 6.12.0-211.74.1.el10_2, kernel-rt-modules-core 6.12.0-211.74.1.el10_2, kernel-rt-debug-modules 6.12.0-211.74.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:95367
  • 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 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% 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

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.