Vulnerability in Linux kernel (CVE-2025-40064)
Summary
Vulnerability in Linux kernel (CVE-2025-40064). 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:
smc: Fix use-after-free in __pnet_find_base_ndev().
syzbot reported use-after-free of net_device in __pnet_find_base_ndev(),
which was called during connect(). [0]
smc_pnet_find_ism_resource() fetches sk_dst_get(sk)->dev and passes
down to pnet_find_base_ndev(), where RTNL is held. Then, UAF happened
at __pnet_find_base_ndev() when the dev is first used.
This means dev had already been freed before acquiring RTNL in
pnet_find_base_ndev().
While dev is going away, dst->dev could be swapped with blackhole_netdev,
and the dev's refcnt by dst will be released.
We must hold dev's refcnt before calling smc_pnet_find_ism_resource().
Also, smc_pnet_find_roce_resource() has the same problem.
Let's use __sk_dst_get() and dst_dev_rcu() in the two functions.
[0]:
BUG: KASAN: use-after-free in __pnet_find_base_ndev+0x1b1/0x1c0 net/smc/smc_pnet.c:926
Read of size 1 at addr ffff888036bac33a by task syz.0.3632/18609
CPU: 1 UID: 0 PID: 18609 Comm: syz.0.3632 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xca/0x240 mm/kasan/report.c:482
kasan_report+0x118/0x150 mm/kasan/report.c:595
__pnet_find_base_ndev+0x1b1/0x1c0 net/smc/smc_pnet.c:926
pnet_find_base_ndev net/smc/smc_pnet.c:946 [inline]
smc_pnet…
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-2025-40064 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-2025-40064" on the vendor's site.
CVE-2025-40064 (Linux kernel) — 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 (unclassified) 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。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2025-40064 linux
- Ubuntu UBUNTU-CVE-2025-40064 linux-hwe-edge
References
- web nvd.nist.gov
- web git.kernel.org
- web git.kernel.org
- web github.com
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org