CVE-2026-52937

tap: fix stack info leak in tap_ioctl() SIOCGIFHWADDR

Published Jun 24, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed

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.

Analysis

Technical 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.

Affected Products

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	< 4b6dcfe0e3dfffd8057a4fc99b3f096c45709905
`3b23a32a63219f51a5298bc55a65ecee866e79d0`	affected	< 37d028a473b0826ad5970b52b791db4a29a23627
`3b23a32a63219f51a5298bc55a65ecee866e79d0`	affected	< 8197905d97099d8b1e3883112bbb497abd20f9f0
`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
`6.1.191`	unaffected	≤ 6.1.*
`6.6.160`	unaffected	≤ 6.6.*
`6.12.114`	unaffected	≤ 6.12.*
`6.18.34`	unaffected	≤ 6.18.*
`7.0.11`	unaffected	≤ 7.0.*
`7.1`	unaffected	≤ *

Configuration 1 [-]

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc1::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc2::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc3::::::
	cpe:2.3:o:linux:linux_kernel:7.1:rc4::::::

No data.

Vendor Product Versions

Linux

Linux Kernel

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

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	—

Remediation

No solution or workaround provided in the CVE record.

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 August 12, 2026 at 05:26 UTC.

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4904-1	linux-6.12 security update
Ubuntu USN	USN-8566-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8568-1	Linux kernel (OEM) vulnerabilities
Ubuntu USN	USN-8569-1	Linux kernel (HWE) vulnerabilities
Ubuntu USN	USN-8593-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8603-1	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8618-1	Linux kernel vulnerabilities
Ubuntu USN	USN-8663-1	Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN	USN-8664-1	Linux kernel (NVIDIA BaseOS) vulnerabilities
Ubuntu USN	USN-8728-1	Linux kernel (GCP) vulnerabilities
Ubuntu USN	USN-8728-2	Linux kernel (Azure) vulnerabilities
Ubuntu USN	USN-8728-3	Linux kernel (Oracle) vulnerabilities

Metrics

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.

Exploit prediction score: < 1% (0.115% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://git.kernel.org/stable/c/05305e832be7b9d65b2b72caacf7d850b3942b2a
https://git.kernel.org/stable/c/37d028a473b0826ad5970b52b791db4a29a23627
https://git.kernel.org/stable/c/4b6dcfe0e3dfffd8057a4fc99b3f096c45709905
https://git.kernel.org/stable/c/719007c3492f0f1f9e9cdbed8ac45ba45bb13eeb
https://git.kernel.org/stable/c/8197905d97099d8b1e3883112bbb497abd20f9f0
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

Nov 7, 2026 7:30 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 30, 2026 12:30 PM Added references View changes

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/4b6dcfe0e3dfffd8057a4fc99b3f096c45709905

Oct 21, 2026 1:00 PM Added references View changes

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/37d028a473b0826ad5970b52b791db4a29a23627 https://git.kernel.org/stable/c/8197905d97099d8b1e3883112bbb497abd20f9f0

Jun 25, 2026 2:30 AM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses	CWE-200

Jun 25, 2026 12:15 AM Weaknesses updated. Added references. Scoring metrics updated View changes

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`

Jun 24, 2026 3:15 PM Weaknesses updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-200

Jun 24, 2026 7:45 AM Description updated. Title updated. First appearance in the feed. Affected versions updated. Affected vendors updated. Added references View changes

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