CVE-2026-100080

xen-netback: Fix UAF when reading statistics data

Published Nov 6, 2026 CVSS 3.1 · 5.6 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

xen-netback: Fix UAF when reading statistics data

The network statistic data in the driver is protected by RCU.
Unfortunately when tearing down the queues after an error during
connecting to the frontend (e.g. due to illegal Xenstore data filled
in by the guest), the statistic data is being freed without
synchronizing the RCU state. In case the data is being read via sysfs
in this phase, access to already freed memory or memory being in new
use is possible.

Fix that by calling synchronize_net() before freeing the queue data.

This is XSA-526 / CVE-2026-100080

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Weaknesses CWE-416
Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.6, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Linux linux
Weaknesses CWE-416
Vendors & Products Linux linux
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: xen-netback: Fix UAF when reading statistics data The network statistic data in the driver is protected by RCU. Unfortunately when tearing down the queues after an error during connecting to the frontend (e.g. due to illegal Xenstore data filled in by the guest), the statistic data is being freed without synchronizing the RCU state. In case the data is being read via sysfs in this phase, access to already freed memory or memory being in new use is possible. Fix that by calling synchronize_net() before freeing the queue data. This is XSA-526 / CVE-2026-100080
Title xen-netback: Fix UAF when reading statistics data
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Nov 13, 2026, 2:17 PM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Nov 6, 2026, 7:17 PM
Modified
Nov 13, 2026, 3:17 PM
Severity
Moderate
Public date
Nov 6, 2026, 6:23 PM