Out-of-Bounds Write in Linux kernel (CVE-2025-39788)
Summary
Out-of-bounds write in Linux kernel (CVE-2025-39788). 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:
scsi: ufs: exynos: Fix programming of HCI_UTRL_NEXUS_TYPE
On Google gs101, the number of UTP transfer request slots (nutrs) is 32,
and in this case the driver ends up programming the UTRL_NEXUS_TYPE
incorrectly as 0.
This is because the left hand side of the shift is 1, which is of type
int, i.e. 31 bits wide. Shifting by more than that width results in
undefined behaviour.
Fix this by switching to the BIT() macro, which applies correct type
casting as required. This ensures the correct value is written to
UTRL_NEXUS_TYPE (0xffffffff on gs101), and it also fixes a UBSAN shift
warning:
UBSAN: shift-out-of-bounds in drivers/ufs/host/ufs-exynos.c:1113:21
shift exponent 32 is too large for 32-bit type 'int'
For consistency, apply the same change to the nutmrs / UTMRL_NEXUS_TYPE
write.
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-2025-39788 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-2025-39788" on the vendor's site.
CVE-2025-39788 (Linux kernel) — CWE-787 / 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.
Out-of-bounds write (CWE-787) 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-2025-39788 linux-lts Fixed in: 6.1.151-r0
- Debian DEBIAN-CVE-2025-39788 linux Fixed in: 5.10.244-1
- Ubuntu UBUNTU-CVE-2025-39788 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 git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web lists.debian.org
- web lists.debian.org
- web cert-portal.siemens.com
- web github.com