High · 7.8 CVE-2025-39815 EUVD-2025-29599GHSA-xcqh-mv9v-g7fj

RISC-V: KVM: fix stack overrun when loading vlenb

Published Sep 16, 2025 · Updated Aug 5, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.8 Package: linux-aws-6.14 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.14 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.14 Package: linux-azure-fde-6.2 Package: linux-azure-fde-6.8 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-azure-nvidia-6.14 Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.14 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.19 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.14 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-6.8 Package: linux-intel Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-lowlatency Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.14 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.3 Package: linux-oracle-5.8 Package: linux-oracle-6.14 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.14 Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.14 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

In the Linux kernel, the following vulnerability has been resolved:

RISC-V: KVM: fix stack overrun when loading vlenb

The userspace load can put up to 2048 bits into an xlen bit stack
buffer. We want only xlen bits, so check the size beforehand.

Affected products

Vendor	Product	Affected	Fixed
Linux	Linux	6.8	6.12.45

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Debian

Security tracker ↗

Release	Package	Fixed in	Advisory
Debian 14	linux	6.16.5-1	—
Debian 13	linux	6.12.48-1	DSA-6008-1

Ubuntu

Security tracker ↗

Release	Package	Fixed in	Advisory
Ubuntu Nvidia-BlueField 24.04 LTS	linux-bluefield	6.8.0-1017.21	—
Ubuntu 25.10	linux-azure-fde	No fix yet	—
Ubuntu 24.04 LTS	linux	6.8.0-106.106	USN-8095-1
Ubuntu 24.04 LTS	linux-aws	6.8.0-1050.53	USN-8095-1
Ubuntu 24.04 LTS	linux-azure	6.8.0-1051.57	USN-8125-1
Ubuntu 24.04 LTS	linux-azure-fde	6.8.0-1058.65	—
Ubuntu 24.04 LTS	linux-azure-nvidia	6.8.0-1039.42	—
Ubuntu 24.04 LTS	linux-gcp	6.8.0-1052.55	USN-8095-1
Ubuntu 24.04 LTS	linux-gke	6.8.0-1048.53	USN-8095-1
Ubuntu 24.04 LTS	linux-gkeop	6.8.0-1035.38	USN-8095-1
Ubuntu 24.04 LTS	linux-ibm	6.8.0-1049.49	USN-8095-1
Ubuntu 24.04 LTS	linux-intel +19	No fix yet	—
Ubuntu 24.04 LTS	linux-lowlatency	6.8.0-106.106.1	USN-8095-1
Ubuntu 24.04 LTS	linux-nvidia	6.8.0-1049.52	USN-8100-1
Ubuntu 24.04 LTS	linux-nvidia-lowlatency	6.8.0-1049.52.1	USN-8100-1
Ubuntu 24.04 LTS	linux-nvidia-tegra	6.8.0-1020.20	—
Ubuntu 24.04 LTS	linux-oracle	6.8.0-1047.48	USN-8095-1
Ubuntu 24.04 LTS	linux-raspi	6.8.0-1050.54	USN-8095-5
Ubuntu 24.04 LTS	linux-xilinx	6.8.0-1028.29	USN-8261-1
Ubuntu 22.04 LTS	linux-aws-6.8	6.8.0-1050.53~22.04.1	USN-8095-4
Ubuntu 22.04 LTS	linux-azure-6.8	6.8.0-1051.57~22.04.1	USN-8126-1
Ubuntu 22.04 LTS	linux-azure-fde-6.8	6.8.0-1058.65~22.04.1	—
Ubuntu 22.04 LTS	linux-gcp-6.8	6.8.0-1052.55~22.04.1	USN-8095-1
Ubuntu 22.04 LTS	linux-hwe-6.8 +1	6.8.0-106.106~22.04.1	USN-8095-1
Ubuntu 22.04 LTS	linux-ibm-6.8	6.8.0-1049.49~22.04.1	USN-8095-1
Ubuntu 22.04 LTS	linux-lowlatency-hwe-6.8	6.8.0-106.106.1~22.04.1	USN-8095-1
Ubuntu 22.04 LTS	linux-nvidia-6.8	6.8.0-1049.52~22.04.1	USN-8100-1
Ubuntu 22.04 LTS	linux-oracle-6.8	6.8.0-1047.48~22.04.1	USN-8095-1
Ubuntu 22.04 LTS	linux-riscv +32	No fix yet	—
Ubuntu 20.04 LTS	linux-gke +28	No fix yet	—

Show 5 more (older releases, extended support, other products)

Release	Package	Fixed in	Advisory
Ubuntu 18.04 LTS	linux-gcp +14	No fix yet	—
Ubuntu 16.04 LTS	linux-hwe-edge	No fix yet	—
Ubuntu Pro Realtime 24.04 LTS	linux-raspi-realtime	6.8.0-2040.41	USN-8095-5
Ubuntu Pro Realtime 24.04 LTS	linux-realtime	6.8.1-1045.46	USN-8095-3
Ubuntu Pro Realtime 24.04 LTS	linux-realtime-6.14	No fix yet	—
Ubuntu Pro Realtime 22.04 LTS	linux-realtime-6.8	6.8.1-1045.46~22.04.1	USN-8095-3
Ubuntu Pro FIPS-updates 24.04 LTS	linux-aws-fips	6.8.0-1050.53+fips1	USN-8095-2
Ubuntu Pro FIPS-updates 24.04 LTS	linux-azure-fips	6.8.0-1052.58+fips1	USN-8165-1
Ubuntu Pro FIPS-updates 24.04 LTS	linux-fips	6.8.0-106.106+fips1	USN-8095-2
Ubuntu Pro FIPS-updates 24.04 LTS	linux-gcp-fips	6.8.0-1052.55+fips1	USN-8095-2

Advisories 12

WID-SEC-2025-2077 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
USN-8100-1 linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
USN-8165-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
USN-8095-1 linux, linux-aws, linux-gcp, linux-gcp-6.8, linux-gke, linux-gkeop, linux-hwe-6.8, linux-ibm, linux-ibm-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oracle, linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8095-2 linux-fips, linux-aws-fips, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8126-1 linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8095-5 linux-raspi, linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8125-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8095-4 linux-aws-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8095-3 linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
USN-8261-1 linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Sep 7, 2026
DSA-6008-1 linux - security update Debian Security (DSA / DLA) · Mar 9, 2026

References