CVE-2026-99223: Linux Vulnerability

Description

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.

Metrics

EPSS Probability

0.17%

5.7th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < 9ebe824d55983c9f063a2c9ef1a08b29812d406f; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < e108b22999edbc6f431466baf6b2016c19b7ed31; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < 9f084ef0beb68091e96ab96f0e95579aac8a77f9; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < 8451d4a4c43127c3b9fdf9fc9ff3fea5539a61f9; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < 13fc051269d670810d9e314061b61c6dd06116a0; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < 61ac0585d9f4344d3dfb84b5edff1fee7d532897; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < 84f7c699f8d139f743c7dc11ef41d085690955bb; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < a113eba06bd1183c614d7994864d6e7054140cb9; >= b2a4df200d570b2c33a57e1ebfa5896e4bc81b69, < de891c73c1cf41ac8de12c07fa2c84d6a912ad0c
Linux	Linux	3.13

References

Timeline

Published: Nov 2, 2026
Last Modified: Nov 3, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-99223?

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.

How severe is CVE-2026-99223?

Severity scoring for CVE-2026-99223 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2026-99223?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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