CVE-2026-97564

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the SMB client where the cifs.idmap key descriptions contain authority-bearing fields, such as owner and group SIDs and uid/gid values in "os:", "gs:", "oi:", and "gi:" formats. The cifs.idmap upcall helper incorrectly treats these as kernel-originating inputs. Because the cifs.idmap key type lacks a vet description hook, userspace can create keys using request key(2) or add key(2) and provide these fields without a legitimate CIFS origin. A request key(2) call with a non-NULL callout triggers a root usermodehelper upcall via /sbin/request-key to cifs.idmap, which then processes the unvetted description within a root context.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.