Vulnerability in Linux kernel (CVE-2026-90174)
Summary
Vulnerability in Linux kernel (CVE-2026-90174). Confidential information can be exposed externally.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix slab-out-of-bounds read in ksmbd_alloc_user()
ksmbd_alloc_user() copies resp->hash_sz bytes out of the mountd IPC
login response with
user->passkey_sz = resp->hash_sz;
user->passkey = kmalloc(resp->hash_sz, KSMBD_DEFAULT_GFP);
if (user->passkey)
memcpy(user->passkey, resp->hash, resp->hash_sz);
resp->hash_sz is a __u16 supplied by the response, but resp->hash[] is
only KSMBD_REQ_MAX_HASH_SZ bytes. A malformed or malicious login
response can set hash_sz well beyond that (up to 65535), so the memcpy()
reads past the end of the response object. ipc_validate_msg() does not
bound hash_sz, so reject any response whose hash_sz exceeds the on-stack
hash[] buffer before allocating and copying.
[ 2030.238706] BUG: KASAN: slab-out-of-bounds in ksmbd_alloc_user+0x278/0x680
[ 2030.240549] Read of size 65535 at addr ffff888121bb6680 by task kworker/4:1/18611
[ 2030.242296]
[ 2030.242710] CPU: 4 UID: 0 PID: 18611 Comm: kworker/4:1 Not tainted 7.1.0-next-20260623-virtme #96 PREEMPT(lazy)
[ 2030.242732] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
[ 2030.242743] Workqueue: ksmbd-io handle_ksmbd_work
[ 2030.242763] Call Trace:
[ 2030.242769]
[ 2030.242776] dump_stack_lvl+0xa2/0xd0
[ 2030.242794] print_address_description+0x77/0x200
[ 2030.242815] ? ksmbd_alloc_user+0x278/0x680
[ 2030.242831] print_report+0x58/0x70
[ 2030.242848] kasan_report+0x117/0…
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-2026-90174 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90174" on the vendor's site.
CVE-2026-90174 (Linux kernel) — CVSS v3 7.1
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 7.1/10). Confidential information can be exposed externally.
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。
References
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com
- web git.kernel.org