Out-of-Bounds Read in Linux kernel (CVE-2026-46020)
Summary
Vulnerability in Linux kernel (CVE-2026-46020). Confidential information can be exposed externally.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-46020 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-46020" on the vendor's site.
CVE-2026-46020 (Linux kernel) — CWE-125 / CVSS v3 7.1
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-46020 linux-lts Fixed in: 6.18.35-r1
- Debian DEBIAN-CVE-2026-46020 linux Fixed in: 7.0.4-1
- Ubuntu UBUNTU-CVE-2026-46020 linux-hwe-edge
References
- advisory nvd.nist.gov
- advisory github.com
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com