Improper resource shutdown or release in Linux kernel - CVE-2026-63970
Published: July 20, 2026
Vulnerability identifier: #VU138672
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-63970
CWE-ID: CWE-404
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
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.
How to mitigate CVE-2026-63970
Install security update from vendor's repository.