Microsoft Security Response Center guidance
Vendor revision: Aug 12, 2026CBL-Mariner Releases
Vendor-listed releases
- 5.15.180.1-1
- 6.6.76.1-1
Vulnerability intelligence
CVE-2025-21666 and is rated Medium severity with a CVSS score of 5.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
CBL-Mariner Releases
Vendor-listed releases
In the Linux kernel, the following vulnerability has been resolved: vsock: prevent null-ptr-deref in vsock_*[has_data|has_space] Recent reports have shown how we sometimes call vsock_*_has_data() 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.
Source: NVD