Vulnerability in Linux kernel (CVE-2026-52969)
Summary
Vulnerability in Linux kernel (CVE-2026-52969). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
KVM: Reject wrapped offset in kvm_reset_dirty_gfn()
kvm_reset_dirty_gfn() guards the gfn range with
if (!memslot || (offset + __fls(mask)) >= memslot->npages)
return;
but offset is u64 and the addition is unchecked. The check can be
silently bypassed by a u64 wrap.
The dirty ring backing those entries is MAP_SHARED at
KVM_DIRTY_LOG_PAGE_OFFSET of the vcpu fd, so the VMM can rewrite the
slot and offset fields of any entry between when the kernel pushes
them and when KVM_RESET_DIRTY_RINGS consumes them. On reset,
kvm_dirty_ring_reset() re-reads the values via READ_ONCE() and feeds
them straight back into this check; only the flags handshake is
treated as the handover, the slot/offset payload is taken on trust.
Crafting two entries
entry[i].offset = 0xffffffffffffffc1
entry[i+1].offset = 0
makes the coalescing loop in kvm_dirty_ring_reset() compute
delta = (s64)(0 - 0xffffffffffffffc1) = 63
which falls in [0, BITS_PER_LONG), so it folds entry[i+1] into the
existing mask by setting bit 63. The trailing kvm_reset_dirty_gfn()
call then sees offset = 0xffffffffffffffc1 and __fls(mask) = 63;
the sum is 0 in u64 and the bounds check passes.
That offset propagates into kvm_arch_mmu_enable_log_dirty_pt_masked()
unchanged. On the legacy MMU path -- kvm_memslots_have_rmaps() ==
true, i.e. shadow paging, any VM that has allocated shadow roots, or
a write-tracked slot -- it reaches gfn_to_rmap(), whic…
Source: GitHub Security Advisories (Global) 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-2026-52969 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-52969" on the vendor's site.
CVE-2026-52969 (Linux kernel) — CWE-129 / CVSS v3 7.8
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-129) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
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-2026-52969 linux-lts Fixed in: 6.1.175-r0
- Debian DEBIAN-CVE-2026-52969 linux Fixed in: 6.1.176-1
- Ubuntu UBUNTU-CVE-2026-52969 linux-hwe-edge
References
- advisory nvd.nist.gov
- advisory access.redhat.com
- advisory github.com
- package git.kernel.org
- report bugzilla.redhat.com
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com
- web security.access.redhat.com