The Linux kernel efivarfs implementation returned success even when an internal lookup failed, allowing the read path to copy uninitialized heap memory into userspace. An attacker who can read efivarfs entries could thus learn kernel data that should not be exposed. This flaw is a classic case of information exposure, identified as CWE-200.

All Linux kernel releases containing the buggy efivarfs code are vulnerable, including kernel 6.19 release candidates up to rc7 as shown by the CPE list. Systems running any unpatched kernel may therefore expose kernel memory contents through the /sys/firmware/efi/efivars interface.

With a CVSS score of 7.8 the vulnerability is classified as high severity, but its EPSS score of <1% indicates exploitation is currently unlikely. The flaw is local, requiring read access to efivarfs, which is normally restricted to privileged users. If the filesystem is mounted with broader permissions or an attacker gains such read access, sensitive kernel data could be leaked. The vulnerability is not listed in the CISA KEV catalog and no active exploit is documented.