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.
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.
Published:
2026-09-25
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
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References
History
Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | afs: Clear stale peer app data after address list changes | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:22:03.666Z
Reserved: 2026-09-24T16:01:01.156Z
Link: CVE-2026-97583
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:09.127
Modified: 2026-09-25T11:17:09.127
Link: CVE-2026-97583
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.