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Fencer Vulns
high 7.8

CVE-2025-38076 json

alloc_tag: allocate percpu counters for module tags dynamically

published 2025-06-18 16 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-18577

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

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

alloc_tag: allocate percpu counters for module tags dynamically

When a module gets unloaded it checks whether any of its tags are still in use and if so, we keep the memory containing module's allocation tags alive until all tags are unused. However percpu counters referenced by the tags are freed by free_module(). This will lead to UAF if the memory allocated by a module is accessed after module was unloaded.

To fix this we allocate percpu counters for module allocation tags dynamically and we keep it alive for tags which are still in use after module unloading. This also removes the requirement of a larger PERCPU_MODULE_RESERVE when memory allocation profiling is enabled because percpu memory for counters does not need to be reserved anymore.

Patch / fix

  • Linux Linux 6.14.9, 6.15
  • linux-aws-6.14 Ubuntu 24.04 LTS 6.14.0-1013.13~24.04.1
  • linux-gcp-6.14 Ubuntu 24.04 LTS 6.14.0-1016.17~24.04.1
  • linux-oem-6.14 Ubuntu 24.04 LTS 6.14.0-1012.12
  • linux-riscv-6.14 Ubuntu 24.04 LTS 6.14.0-32.32.1~24.04.1
  • linux-oracle-6.14 Ubuntu 24.04 LTS 6.14.0-1013.13~24.04.1
  • linux-azure-nvidia-6.14 Ubuntu 24.04 LTS 6.14.0-1007.7
  • linux-realtime-6.14 Ubuntu Pro Realtime 24.04 LTS 6.14.0-1012.12~24.04.1

ubuntu advisories UBUNTU-CVE-2025-38076

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-2025-38076 updated

kernel: alloc_tag: allocate percpu counters for module tags dynamically

  • 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 Red Hat Enterprise Linux 10 kernel
    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 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 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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