CVE-2025-21666: vsock: prevent null-ptr-deref in vsock_*[has_data|has_space]
In the Linux kernel, the following vulnerability has been resolved:
vsock: prevent null-ptr-deref in vsock[hasdata|hasspace]
Recent reports have shown how we sometimes call vsockhasdata() when a vsock socket has been de-assigned from a transport (see attached links), but we shouldn't.
Previous commits should have solved the real problems, but we may have more in the future, so to avoid null-ptr-deref, we can return 0 (no space, no data available) but with a warning.
This way the code should continue to run in a nearly consistent state and have a warning that allows us to debug future problems.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1 - Upgrade
Upgrade
debian/linux-6.1to a version that resolves this vulnerability.Fixed in 6.1.129-1~deb11u1
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21666?
CVE-2025-21666 is classified as a moderate severity vulnerability.
How do I fix CVE-2025-21666?
To fix CVE-2025-21666, you should update your Linux kernel to the latest stable version that resolves this issue.
Which versions of the Linux kernel are affected by CVE-2025-21666?
CVE-2025-21666 affects Linux kernel versions from 5.5 up to 6.13-rc7.
What kind of issue does CVE-2025-21666 address?
CVE-2025-21666 addresses a null pointer dereference in the vsock_*[has_data|has_space] functions.
Is exploitation of CVE-2025-21666 possible remotely?
Exploitation of CVE-2025-21666 typically requires local access to the affected system.