AZL-112547: CVE-2026-99223 affecting package kernel 6.6.159.1-1
In the Linux kernel, the following vulnerability has been resolved:
keys: make keyring indexes independent of kernel addresses
KEYCTLREAD returns the serial numbers in a keyring in associative-array traversal order. The first word of the index is a public, deterministic hash of the type pointer, domain pointer and description. An unprivileged user can therefore insert keys with known descriptions, predict their order for each possible KASLR slide, and recover the kernel image address. On an x86-64 build with 16 MiB alignment, 45 user keys suffice to distinguish the candidate slides.
Remove the addresses from the whole index, not just its first hash word. Assign each key type and domain a nonzero 64-bit ID and hash those IDs and the description with a once-initialized SipHash key. Use the full IDs in the later index chunks as well. Truncating or hashing the IDs there would lose the guarantee that distinct type/domain/description tuples have a differing index bit.
Allocate IDs lazily since private key types need not be registered. Cache them in the index key so tree walks and copies of an existing index do not need to dereference a type descriptor that may have been unregistered. Keep the 32-bit chunk layout and diffobjects() bit offsets consistent, and retain the separate root slot for keyrings used by recursive search. The key comparison, permissions and userspace data format are unchanged; only the address-dependent in-memory ordering is replaced.
Affected Software
Event History
Frequently Asked Questions
What access does an attacker need to exploit this issue?
An unprivileged user must be able to insert keys with known descriptions and read keyring serial numbers through KEYCTL_READ. They can use the observed associative-array traversal order to predict candidate KASLR slides and recover the kernel image address.
Which environment has a demonstrated exploitation estimate?
The description gives an x86-64 build with 16 MiB alignment as an example. In that case, 45 user keys are sufficient to distinguish the candidate KASLR slides.
What is the security impact of successful exploitation?
Successful exploitation discloses the kernel image address by defeating KASLR address randomization. The provided information does not describe code execution or privilege escalation as a direct result.