SB20260720255 - Improper resource shutdown or release in Linux kernel vmw_vsock

Description

This security bulletin contains information about 1 vulnerability.

1) Improper resource shutdown or release (CVE-ID: CVE-2026-63970)

CWE-ID: CWE-404 - Improper Resource Shutdown or Release

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper resource shutdown or release in virtio_transport_alloc_skb() in the vsock/virtio transport when processing fixed-buffer vectored zerocopy input that hits MAX_SKB_FRAGS. A local user can trigger a partial attachment of managed fragments to cause a denial of service.

Exploitation occurs on the rollback path after io_sg_from_iter() returns -EMSGSIZE, causing an skb with managed fragment references but no bound uarg to be freed through the ordinary fragment unref path.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1e584c304cfb94a759417130b1fc6d30b30c4cce
• https://git.kernel.org/stable/c/5d317573f1d48e76cce5fb6250452b6e4102e0fb
• https://git.kernel.org/stable/c/b62e2b2b4a50953ca952f3cd3f77dd62dc50fd5d