Vulnerability in Linux kernel (CVE-2026-74257)
Summary
Vulnerability in Linux kernel (CVE-2026-74257). 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:
sockmap: Fix use-after-free in udp_bpf_recvmsg()
syzbot reported use-after-free of struct sk_msg in sk_msg_recvmsg(). [0]
sk_msg_recvmsg() peeks sk_msg from psock->ingress_msg under a lock,
but its processing is lockless.
Thus, sk_msg_recvmsg() must be serialised by callers, otherwise
multiple threads could touch the same sk_msg.
For example, TCP uses lock_sock(), and AF_UNIX uses unix_sk(sk)->iolock.
Initially, udp_bpf_recvmsg() had used lock_sock(), but the cited
commit removed it.
Let's serialise sk_msg_recvmsg() with lock_sock() in udp_bpf_recvmsg().
Note that holding spin_lock_bh(&sk->sk_receive_queue.lock) is not
an option due to copy_page_to_iter() in sk_msg_recvmsg().
[0]:
BUG: KASAN: slab-use-after-free in sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428
Read of size 4 at addr ffff88814cdcf000 by task syz.0.24/6020
CPU: 1 UID: 0 PID: 6020 Comm: syz.0.24 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xba/0x230 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
sk_msg_recvmsg+0xb54/0xc30 net/core/skmsg.c:428
udp_bpf_recvmsg+0x4bd/0xe00 net/ipv4/udp_bpf.c:84
inet_recvmsg+0x260/0x270 net/ipv4/af_inet.c:891
sock_recvmsg_nosec net/socket.c:1078 [inline]
sock_recvmsg+0…
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-2026-74257 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-2026-74257" on the vendor's site.
CVE-2026-74257 (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。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-74257 linux-lts
- Debian DEBIAN-CVE-2026-74257 linux
- Ubuntu UBUNTU-CVE-2026-74257 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