Use-After-Free in Linux kernel (CVE-2025-38209)
Summary
Vulnerability in Linux kernel (CVE-2025-38209). 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:
nvme-tcp: remove tag set when second admin queue config fails
Commit 104d0e2f6222 ("nvme-fabrics: reset admin connection for secure
concatenation") modified nvme_tcp_setup_ctrl() to call
nvme_tcp_configure_admin_queue() twice. The first call prepares for
DH-CHAP negotitation, and the second call is required for secure
concatenation. However, this change triggered BUG KASAN slab-use-after-
free in blk_mq_queue_tag_busy_iter(). This BUG can be recreated by
repeating the blktests test case nvme/063 a few times [1].
When the BUG happens, nvme_tcp_create_ctrl() fails in the call chain
below:
nvme_tcp_create_ctrl()
nvme_tcp_alloc_ctrl() new=true ... Alloc nvme_tcp_ctrl and admin_tag_set
nvme_tcp_setup_ctrl() new=true
nvme_tcp_configure_admin_queue() new=true ... Succeed
nvme_alloc_admin_tag_set() ... Alloc the tag set for admin_tag_set
nvme_stop_keep_alive()
nvme_tcp_teardown_admin_queue() remove=false
nvme_tcp_configure_admin_queue() new=false
nvme_tcp_alloc_admin_queue() ... Fail, but do not call nvme_remove_admin_tag_set()
nvme_uninit_ctrl()
nvme_put_ctrl() ... Free up the nvme_tcp_ctrl and admin_tag_set
The first call of nvme_tcp_configure_admin_queue() succeeds with
new=true argument. The second call fails with new=false argument. This
second call does not call nvme_remove_admin_tag_set() on failure, due to
the new=false ar…
Source: NIST National Vulnerability Database NVD
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-2025-38209 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2025-38209" on the vendor's site.
CVE-2025-38209 (Linux kernel) — CWE-416 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / 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.
Use-after-free (CWE-416) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: Critical (CVSS 9.8/10). 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-2025-38209 linux-lts Fixed in: 6.18.35-r1
- Ubuntu UBUNTU-CVE-2025-38209 linux-hwe-edge
References
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org