NULL pointer dereference in Linux

CVE-2025-21669

In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: discard packets if the transport changes If the socket has been de-assigned or assigned to another transport, we must discard any packets received because they are not expected and would cause issues when we access vsk->transport. A possible scenario is described by Hyunwoo Kim in the attached link, where after a first connect() interrupted by a signal, and a second connect() failed, we can find `vsk->transport` at NULL, leading to a NULL pointer dereference.

EPSS: 0.002 (12.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-21669?
CVE-2025-21669 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.8/10. Published 2025-01-31.
How severe is CVE-2025-21669?
High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2025-21669 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.