CVE-2025-39718 vsock/virtio: Validate length in packet header before skb_put()
A missing length validation in the Linux kernel vsock/virtio driver allows a malicious host to cause memory corruption in the guest.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39718?
CVE-2025-39718 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 5 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
vsock/virtio: Validate length in packet header before skb_put()
When receiving a vsock packet in the guest, only the virtqueue buffer size is validated prior to virtio_vsock_skb_rx_put(). Unfortunately, virtio_vsock_skb_rx_put() uses the length from the packet header as the length argument to skb_put(), potentially resulting in SKB overflow if the host has gone wonky.
Validate the length as advertised by the packet header before calling virtio_vsock_skb_rx_put().
Weakness: CWE-787
Which versions are affected by CVE-2025-39718?
It affects 2 products.
Linux distribution packages (40)
bpftool AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-abi-stablelists AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-core AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-cross-headers AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-debug AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-debug-core AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-debug-devel AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-debug-modules AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-debug-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-devel AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-doc AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-headers AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-modules AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-rt AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-core AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-debug AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-debug-core AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-debug-devel AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-debug-modules AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-debug-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-devel AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-modules AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-rt-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.84.1.rt7.425.el8_10 |
kernel-tools AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-tools-libs AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-tools-libs-devel AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-zfcpdump AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-zfcpdump-core AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-zfcpdump-devel AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-zfcpdump-modules AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
kernel-zfcpdump-modules-extra AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
perf AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
python3-perf AlmaLinux:8 | All versions | 4.18.0-553.84.1.el8_10 |
bpftool Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.84.1.el8_10 |
bpftool-debuginfo Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.84.1.el8_10 |
kernel Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.84.1.el8_10 |
kernel-abi-stablelists Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.84.1.el8_10 |
kernel-core Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.84.1.el8_10 |
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39718?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-39718 being exploited?
There is no known exploitation of CVE-2025-39718 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as ALSA-2025:21397, ALSA-2025:21398, AZL-66947, BELL-CVE-2025-39718, DEBIAN-CVE-2025-39718, GHSA-4whh-7h4c-xh74 and 6 more.