Categories
CVE-2025-39788 high CVSS 7.8

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.

❓ What is the problem

Out-of-bounds write (CWE-787) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

  1. 1
    Identify 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。

  2. 2
    Post-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

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"5.9.0"},{"fixed":"5.10.241"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.190"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.149"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.103"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.44"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.16.4"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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