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Fencer Vulns
medium 5.5

CVE-2025-38049 json

x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors

published 2025-04-18 18 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-11827

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

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

x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors

Commit

6eac36bb9eb0 ("x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid")

added logic that causes resctrl to search for the CLOSID with the fewest dirty cache lines when creating a new control group, if requested by the arch code. This depends on the values read from the llc_occupancy counters. The logic is applicable to architectures where the CLOSID effectively forms part of the monitoring identifier and so do not allow complete freedom to choose an unused monitoring identifier for a given CLOSID.

This support missed that some platforms may not have these counters. This causes a NULL pointer dereference when creating a new control group as the array was not allocated by dom_data_init().

As this feature isn't necessary on platforms that don't have cache occupancy monitors, add this to the check that occurs when a new control group is allocated.

Patch / fix

  • Linux Linux 6.12.23, 6.13.11, 6.14.2, 6.15
  • linux Debian 14, Debian 13 6.12.25-1

debian advisories DEBIAN-CVE-2025-38049

  • linux-gcp-6.11 Ubuntu 24.04 LTS 6.11.0-1016.16~24.04.1
  • linux-hwe-6.11 Ubuntu 24.04 LTS 6.11.0-28.28~24.04.1
  • linux-oem-6.11 Ubuntu 24.04 LTS 6.11.0-1024.24
  • linux-azure-6.11 Ubuntu 24.04 LTS 6.11.0-1018.18~24.04.1
  • linux-nvidia-6.11 Ubuntu 24.04 LTS 6.11.0-1012.12
  • linux-lowlatency-hwe-6.11 Ubuntu 24.04 LTS 6.11.0-1015.16~24.04.2

ubuntu advisories UBUNTU-CVE-2025-38049

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

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-2025-38049 updated cvss 4.4

kernel: x86/resctrl: Fix allocation of cleanest CLOSID on platforms with no monitors

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • 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
    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
partial
Assessed
13 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.