What’s Vulnerable › Vulnerabilities

CVE-2025-39718: vsock/virtio: Validate length in packet header before skb_put()

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-09-05 · updated 2026-10-19
• Weakness: CWE-787

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().

Affected products

• Debian Linux: 11.0
• Linux kernel: from 6.1.63 before 6.1.149; from 6.3 before 6.6.103; from 6.7 before 6.12.44; from 6.13 before 6.16.4 — fixed in 6.1.149, 6.12.44, 6.16.4, 6.6.103

How to fix

Upgrade to a fixed version: Linux kernel 6.1.149, 6.12.44, 6.16.4, 6.6.103. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0dab92484474587b82e8e0455839eaf5ac7bf894
• https://git.kernel.org/stable/c/676f03760ca1d69c2470cef36c44dc152494b47c
• https://git.kernel.org/stable/c/969b06bd8b7560efb100a34227619e7d318fbe05
• https://git.kernel.org/stable/c/ee438c492b2e0705d819ac0e25d04fae758d8f8f
• https://git.kernel.org/stable/c/faf332a10372390ce65d0b803888f4b25a388335
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
• https://cert-portal.siemens.com/productcert/html/ssa-032379.html

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