Vulnerability in Linux kernel (CVE-2026-64295)
Summary
Vulnerability in Linux kernel (CVE-2026-64295). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
mm: page_ext: add count limit to page_ext_iter_next to prevent invalid PFN access
The page_ext iteration API does not validate if the PFN still belongs to a
valid section while advancing the iterator. When dynamically adding
memory in the hotplug path, it can lead to a NULL pointer dereference
during page_ext_lookup at the boundary of the last valid section when
iterator count equals __pgcount.
The for_each_page_ext() macro calls page_ext_iter_next() as its loop
increment. for_each_page_ext() does a "__page_ext =
page_ext_iter_next(&__iter)" at the end. This causes page_ext_iter_next()
to increment iter->index past __pgcount and call page_ext_lookup(start_pfn
- __pgcount). During memory hotplug (online), the PFN at start_pfn +
__pgcount may belong to a section that has not yet been initialized,
causing page_ext_lookup() to trigger a NULL pointer dereference.
[ 14.555124][ T846] Call trace:
[ 14.555125][ T846] lookup_page_ext+0x6c/0x108 (P)
[ 14.555127][ T846] page_ext_lookup+0x30/0x3c
[ 14.555129][ T846] __reset_page_owner+0x11c/0x260
[ 14.571201][ T846] __free_pages_ok+0x5e8/0x8e0
[ 14.571204][ T846] __free_pages_core+0x78/0xf0
[ 14.571206][ T846] generic_online_page+0x14/0x24
[ 14.597782][ T846] online_pages+0x178/0x30c
[ 14.597784][ T846] memory_block_change_state+0x284/0x32c
[ 14.597787][ T846] memory_subsys_online+0x4c/0x64
[ 14.597789][ T846] device_onl…
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-2026-64295 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-64295" on the vendor's site.
CVE-2026-64295 (Linux kernel) — CWE-476 / CVSS v3 5.5
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.
A vulnerability (CWE-476) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: Medium (CVSS 5.5/10). Risk of unauthorized operations or information disclosure.
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-2026-64295 linux-lts Fixed in: 6.18.43-r0
- Debian DEBIAN-CVE-2026-64295 linux Fixed in: 7.1.4-1
- Ubuntu UBUNTU-CVE-2026-64295 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