CVE Catalog

CVE-2026-99223

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, keyring indexes contained kernel addresses (hashes of type and domain pointers), allowing an unprivileged user to predict key ordering and recover the kernel image address, defeating KASLR. The fix removes addresses from the entire index, replacing them with lazily allocated 64-bit IDs hashed with a SipHash key.

Risk Assessment

Disclosure of the kernel image address significantly eases exploitation of other kernel vulnerabilities (KASLR bypass). The risk applies to systems where unprivileged users can create keys.

Recommendation

Update the Linux kernel to a version containing the fix. Until then, restrict the ability of unprivileged users to create keyrings where feasible.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: keys: make keyring indexes independent of kernel addresses KEYCTL_READ 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 diff_objects() 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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS