CVE-2026-52937 - Vulnerability Details

- tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

Description

In the Linux kernel, the following vulnerability has been resolved:

tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an
uninitialised on-stack struct sockaddr_storage to userspace via
ifr_hwaddr, but netif_get_mac_address() only writes sa_family and
dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised.

Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a
macvtap chardev returns kernel .text and direct-map pointers, defeating
KASLR.

Initialise ss at declaration.

Published: 2026-06-24

Score: 5.5 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

In the Linux kernel, the tap driver contains a flaw that causes the to copy 16 bytes from an uninitialized on‑stack structure, leaving eight bytes of kernel stack data exposed. An attacker who can call this ioctl on a macvtap character device can read kernel .text and direct‑map addresses, which defeats Kernel Address Space Layout Randomization.

Affected Systems

Any Linux system running a kernel version that predates the commit that added proper initialization of the sockaddr_storage in tap_ioctl is vulnerable. This includes all standard Linux kernel releases until the patch is applied, regardless of distribution, as the affected code is part of the core kernel.

Risk and Exploitability

The EPSS score is below 1%, indicating a very low exploitation probability, and the CVSS score of 5.5 classifies the vulnerability as moderate. The bug is not listed in CISA KEV. Although the score is moderate, the leak of kernel addresses provides a foothold that can aid further attacksASLR is bypassed. The likely attack vector is local or privileged access to the macvtap device, inferred from the need to perform SIOCGIFHWADDR on that character device.

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
`3b23a32a63219f51a5298bc55a65ecee866e79d0`	affected	< 719007c3492f0f1f9e9cdbed8ac45ba45bb13eeb
`3b23a32a63219f51a5298bc55a65ecee866e79d0`	affected	< 05305e832be7b9d65b2b72caacf7d850b3942b2a
`3b23a32a63219f51a5298bc55a65ecee866e79d0`	affected	< bddc09212c24934643bd44fc794748d2bbb3b6cd
`176188cff67ec1aa55103647b61d02315cc38e98`	affected	—
`1fc205d9e400f069ebf30d3faa6ec2bab2cbd7b4`	affected	—
`4d0ae760c02c98fc78b78d3a0509896bc648ad1c`	affected	—
`5.4.103`	affected	< 5.5
`5.10.21`	affected	< 5.11
`5.11.4`	affected	< 5.12

Linux

affected

Version	Status	Constraints
`5.12`	affected	—
`0`	unaffected	< 5.12
`6.18.34`	unaffected	≤ 6.18.*
`7.0.11`	unaffected	≤ 7.0.*
`7.1`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[3b23a32a63219f51a5298bc55a65ecee866e79d0,719007c3492f0f1f9e9cdbed8ac45ba45bb13eeb)`	affected	code_commit	—
`[3b23a32a63219f51a5298bc55a65ecee866e79d0,05305e832be7b9d65b2b72caacf7d850b3942b2a)`	affected	code_commit	—
`[3b23a32a63219f51a5298bc55a65ecee866e79d0,bddc09212c24934643bd44fc794748d2bbb3b6cd)`	affected	code_commit	—
`176188cff67ec1aa55103647b61d02315cc38e98`	affected	code_commit	—
`1fc205d9e400f069ebf30d3faa6ec2bab2cbd7b4`	affected	code_commit	—
`4d0ae760c02c98fc78b78d3a0509896bc648ad1c`	affected	code_commit	—
`[5.4.103,5.5)`	affected	semver	—
`[5.10.21,5.11)`	affected	semver	—
`[5.11.4,5.12)`	affected	semver	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`5.12`	affected	semver	—
`[0,5.12)`	unaffected	semver	—
`[6.18.34,6.19.0)`	unaffected	semver	—
`[7.0.11,7.1.0)`	unaffected	semver	—
`[7.1,*]`	unaffected	generic	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Apply a kernel update that includes the tap driver fix for proper sockaddr_storage initialization
If an immediate patch is not possible, restrict or remove unnecessary macvtap devices and apply strict file permissions or ACLs to the macvtap device to limit access to trusted users
Continuously monitor vendor advisories and security feeds for related kernel exploits or additional mitigations

Generated by OpenCVE AI on June 25, 2026 at 03:25 UTC.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00112.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/05305e832be7b9d65b2b72caacf7d850b3942b2a
https://git.kernel.org/stable/c/719007c3492f0f1f9e9cdbed8ac45ba45bb13eeb
https://git.kernel.org/stable/c/bddc09212c24934643bd44fc794748d2bbb3b6cd
https://lore.kernel.org/linux-cve-announce/2026062434-CVE-2026-52937-62eb@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-52937
https://www.cve.org/CVERecord?id=CVE-2026-52937

History

Thu, 25 Jun 2026 02:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200

Thu, 25 Jun 2026 00:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-909
References		https://lore.kernel.org/linux-cve-announce/2026062434-CVE-2026-52937-62eb@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-52937 https://www.cve.org/CVERecord?id=CVE-2026-52937
Metrics	threat_severity `None`	cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Moderate`

Wed, 24 Jun 2026 15:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200

Wed, 24 Jun 2026 07:45:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR In the SIOCGIFHWADDR path, tap_ioctl() copies 16 bytes of an uninitialised on-stack struct sockaddr_storage to userspace via ifr_hwaddr, but netif_get_mac_address() only writes sa_family and dev->addr_len (6 for Ethernet) bytes, leaving sa_data[6..13] uninitialised. Those 8 trailing bytes leak kernel stack contents; SIOCGIFHWADDR on a macvtap chardev returns kernel .text and direct-map pointers, defeating KASLR. Initialise ss at declaration.
Title		tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR
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/05305e832be7b9d65b2b72caacf7d850b3942b2a https://git.kernel.org/stable/c/719007c3492f0f1f9e9cdbed8ac45ba45bb13eeb https://git.kernel.org/stable/c/bddc09212c24934643bd44fc794748d2bbb3b6cd

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-06-24T07:14:27.305Z

Updated: 2026-06-24T07:14:27.305Z

Reserved: 2026-06-09T07:44:35.370Z

Link: CVE-2026-52937

Vulnrichment

No data.

NVD

No data.

Redhat

Severity : Moderate

Publid Date: 2026-06-24T00:00:00Z

Links: CVE-2026-52937 - Bugzilla

OpenCVE Enrichment

Updated: 2026-06-25T03:30:17Z

Weaknesses

CWE-909
Missing Initialization of Resource

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Subscriptions

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