Vulnerability in Linux kernel (CVE-2026-53183)
Summary
Vulnerability in Linux kernel (CVE-2026-53183). Risk of unauthorized operations or information disclosure. Exploitable via window.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
mptcp: allow subflow rcv wnd to shrink
In MPTCP connection, the window field in the TCP header refers to the
MPTCP-level rcv_nxt and it's right edge should not move backward. Such
constraint is enforced at DSS option generation time.
At the same time, the TCP stack ensures independently that the TCP-level
rcv wnd right's edge does not move backward. That in turn causes artificial
inflating of the MPTCP rcv window when the incoming data is acked at the
TCP level and is OoO in the MPTCP sequence space (or lands in the backlog).
As a consequence, the incoming traffic can exceed the receiver rcvbuf size
even when the sender is not misbehaving.
Prevent such scenario forcibly allowing the TCP subflow to shrink the
TCP-level rcv wnd regardless of the current netns setting.
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-2026-53183 has been found in Linux kernel.
Attackers can target a specific entry point like window over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-53183" on the vendor's site.
CVE-2026-53183 (Linux kernel) — CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: window
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 (unclassified) exists in Linux kernel. Attackers reach the vulnerable code path via window without authentication.
Check the vendor advisory for the affected versions of Linux kernel. Attack surface: window.
Severity: High (CVSS 7.5/10). 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-2026-53183 linux-lts Fixed in: 6.1.177-r0
- Debian DEBIAN-CVE-2026-53183 linux Fixed in: 6.1.176-1
- Ubuntu UBUNTU-CVE-2026-53183 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 git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web github.com
- web cert-portal.siemens.com