Vulnerability in Linux kernel (CVE-2026-90200)
Summary
Vulnerability in Linux kernel (CVE-2026-90200). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: fix integer overflow in MFT cluster validation
In ntfs_init_from_boot(), the boot sector's MFT cluster numbers are
validated against the volume size with:
if (mlcn * sct_per_clst >= sectors ||
mlcn2 * sct_per_clst >= sectors)
goto out;
mlcn and mlcn2 are u64 fields read directly from the boot sector.
sct_per_clst is bounded above by 4096 (true_sectors_per_clst() plus
the is_power_of_2() check below it), but the multiplication is done
in u64 and wraps when mlcn (or mlcn2) is large enough -- e.g. mlcn
near 2^62 with sct_per_clst == 4 wraps to 0, which compares below
any non-zero 'sectors', so the check is bypassed and the malformed
record is accepted.
The accepted mlcn is then used unchanged in
sbi->mft.lbo = mlcn << cluster_bits;
In practice the resulting reads fail at the block layer (sb_bread()
returns NULL via grow_buffers()'s check_mul_overflow() guard), so
today this manifests as mount failing in odd places rather than as
something more dangerous, but the validation step is still wrong
and there is no reason for callers to rely on the block layer to
catch a value that should never have been accepted in the first
place.
Use check_mul_overflow() to compute the two sector positions and
fail the mount if either multiplication wraps; this preserves the
existing semantics (mlcn * sct_per_clst >= sectors) instead of
switching to division (mlcn >= sectors / sct_per_clst), which
would t…
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-2026-90200 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-90200" on the vendor's site.
CVE-2026-90200 (Linux kernel)
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: ?. 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。
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com