CVE-2026-97583 - Vulnerability Details

- afs: Clear stale peer app data after address list changes

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.

Published: 2026-09-25

Score: 7.5 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The flaw lies in the AFS component of the Linux kernel where stale peer application data is not cleared after an address list change. A CS disabled entry remains referenced, causing a use‑after‑free that is detected by KASAN as a slab use‑after‑free inside afs_find_server. This allows a process to read and use freed kernel memory, which can result in an unexpected kernel crash or corruption of kernel state. If exploited, the attacker could potentially gain elevated privileges or cause a denial of service.

Affected Systems

All installations of the Linux kernel that include AFS support and have not yet incorporated the described patch. No specific kernel versions are listed, so any kernel build containing the vulnerable afs_* routines is potentially affected.

Risk and Exploitability

The vulnerability carries a CVSS score of 7.5 and an EPSS score of less than 1 %. It is not listed in the CISA KEV catalog. The likely exploitation path involves manipulating the RxRPC connection or forcing a server to refresh its address list, which can be triggered by a local or compromised user. No public exploit is currently known.

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

unaffected

Version	Status	Constraints
`39ba6af83a7f9dee3e6a7916f41a48bcbda54eba`	affected	< 3afb988fd0411707bdafb9b321086fff0da28aae
`40e8b52fe8c8ab6920ea5f59c5469b6918cce624`	affected	< c7f77a11a1e719192c7262aad38a3919aec62c21
`40e8b52fe8c8ab6920ea5f59c5469b6918cce624`	affected	< 7f7f5589d048821dea316cbac9b37d27eaf7530e
`40e8b52fe8c8ab6920ea5f59c5469b6918cce624`	affected	< ba0623fc19a424f4745394c499f9f28a8d88d397
`6.12.101`	affected	< 6.12.111

Linux

affected

Version	Status	Constraints
`6.15`	affected	—
`0`	unaffected	< 6.15
`6.12.111`	unaffected	≤ 6.12.*
`6.18.53`	unaffected	≤ 6.18.*
`7.2.7`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[39ba6af83a7f9dee3e6a7916f41a48bcbda54eba,3afb988fd0411707bdafb9b321086fff0da28aae)`	affected	code_commit	—
`[40e8b52fe8c8ab6920ea5f59c5469b6918cce624,c7f77a11a1e719192c7262aad38a3919aec62c21)`	affected	code_commit	—
`[40e8b52fe8c8ab6920ea5f59c5469b6918cce624,7f7f5589d048821dea316cbac9b37d27eaf7530e)`	affected	code_commit	—
`[40e8b52fe8c8ab6920ea5f59c5469b6918cce624,ba0623fc19a424f4745394c499f9f28a8d88d397)`	affected	code_commit	—
`[6.12.101,6.12.111)`	affected	semver	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`6.15`	affected	generic	—
`[0,6.15)`	unaffected	generic	—
`[6.12.111,6.13.0]`	unaffected	semver	—
`[6.18.53,6.19.0]`	unaffected	semver	—
`[7.2.7,7.3.0]`	unaffected	semver	—
`[7.3-rc3,*]`	unaffected	generic	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Update the kernel to a release that contains the patch fixing stale peer application data cleanup (e.g., apply the change from commit 3afb988fd0411707bdafb9b321086fff0da28aae and later stable branches).
If a patched kernel is not yet available, disable or restrict use of AFS/RxRPC services until the fix is applied and monitor system logs for KASAN or OOPS messages that may indicate the use‑after‑free.
Enable kernel hardening mechanisms such as CONFIG_KASAN or CONFIG_SLABINFO to detect similar errors and reboot after applying the patch to ensure memory is correctly reclaimed.

Generated by OpenCVE AI on October 1, 2026 at 09:01 UTC.

Tracking

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Advisories

Source	ID	Title
Debian DLA	DLA-4817-1	linux-6.12 security update
Debian DSA	DSA-6528-1	linux security update

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00408.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97583.mbox
https://git.kernel.org/stable/c/3afb988fd0411707bdafb9b321086fff0da28aae
https://git.kernel.org/stable/c/7f7f5589d048821dea316cbac9b37d27eaf7530e
https://git.kernel.org/stable/c/ba0623fc19a424f4745394c499f9f28a8d88d397
https://git.kernel.org/stable/c/c7f77a11a1e719192c7262aad38a3919aec62c21
https://nvd.nist.gov/vuln/detail/CVE-2026-97583
https://www.cve.org/CVERecord?id=CVE-2026-97583

History

Tue, 29 Sep 2026 20:00:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-416

Tue, 29 Sep 2026 13:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-825
References		https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97583.mbox https://nvd.nist.gov/vuln/detail/CVE-2026-97583 https://www.cve.org/CVERecord?id=CVE-2026-97583
Metrics	threat_severity `None`	threat_severity `Moderate`

Fri, 25 Sep 2026 22:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-416

Fri, 25 Sep 2026 15:00:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}`

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

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-09-25T10:22:03.666Z

Updated: 2026-10-19T09:09:46.971Z

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: 2026-10-19T10:17:27.647

Link: CVE-2026-97583

Redhat

Severity : Moderate

Publid Date: 2026-09-25T00:00:00Z

Links: CVE-2026-97583 - Bugzilla

OpenCVE Enrichment

Updated: 2026-10-01T09:15:06Z

Weaknesses

CWE-825
Expired Pointer Dereference

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction Required

Subscriptions

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