Skip to content
Fencer Vulns
high 7.1

CVE-2026-46020 json

mm/damon/core: validate damos_quota_goal->nid for node_mem_{used,free}_bp

published 2026-05-27 5 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-32401

cvss
7.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

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

mm/damon/core: validate damos_quota_goal->nid for node_mem_{used,free}_bp

Patch series "mm/damon/core: validate damos_quota_goal->nid".

node_mem[cg]_{used,free}_bp DAMOS quota goals receive the node id. The node id is used for si_meminfo_node() and NODE_DATA() without proper validation. As a result, privileged users can trigger an out of bounds memory access using DAMON_SYSFS. Fix the issues.

The issue was originally reported [1] with a fix by another author. The original author announced [2] that they will stop working including the fix that was still in the review stage. Hence I'm restarting this.

This patch (of 2):

Users can set damos_quota_goal->nid with arbitrary value for node_mem_{used,free}_bp. But DAMON core is using those for si_meminfo_node() without the validation of the value. This can result in out of bounds memory access. The issue can actually triggered using DAMON user-space tool (damo), like below.

$ sudo ./damo start --damos_action stat \ --damos_quota_goal node_mem_used_bp 50% -1 \ --damos_quota_interval 1s $ sudo dmesg [...] [ 65.565986] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000098

Fix this issue by adding the validation of the given node. If an invalid node id is given, it returns 0% for used memory ratio, and 100% for free memory ratio.

Patch / fix

  • Linux Linux 6.18.27, 7.0.4, 7.1
  • linux Debian 14 7.0.4-1

debian advisories DEBIAN-CVE-2026-46020

  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1007.7
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1009.9
  • linux-azure Ubuntu 26.04 LTS 7.0.0-1010.10
  • linux-raspi Ubuntu 26.04 LTS 7.0.0-1014.14
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-27.27.1
  • linux-nvidia Ubuntu 26.04 LTS 7.0.0-1013.13

ubuntu advisories UBUNTU-CVE-2026-46020

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-source openSUSE Tumbleweed 7.0.11-1.1

opensuse advisories openSUSE-SU-2026:10954-1

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-2026-46020 updated

kernel: mm/damon/core: validate damos_quota_goal->nid for node_mem_{used,free}_bp

  • 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

0.12% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.