CVE-2026-63991 - Vulnerability Details

- Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt()

Description

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

Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt()

The skb_clone() function can return NULL if memory allocation fails.
send_mcast_pkt() calls skb_clone() without checking the return value, which
can lead to a NULL pointer dereference in send_pkt() when it dereferences
skb->data.
Add a NULL check after skb_clone() and skip the peer if the clone fails.

Published: 2026-07-19

Score: 5.5 Medium

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

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
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< 9afcb5ea080af13aab37930da627db43bd277665
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< 9903a04becf059e44cccf625e23689b7d4378384
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< d630c4b25f36e0e68461561e4c70957ec37fdedd
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< b06203ac5f12929d79146bb9f063c2af1d679e63
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< 3d5d81d294ba09487c86bc4ba33dc4a4bec5d215
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< e673889a35a5e4c586d0fae67d8755ca4367d3e2
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< 2061d080a013c0ec0a56162cd501fb36d2befc26
`18722c247023035b9e2e2a08a887adec2a9a6e49`	affected	< 3c40d381ce04f9575a5d8b542898183c3b4b38dc

Linux

affected

Version	Status	Constraints
`3.14`	affected	—
`0`	unaffected	< 3.14
`5.10.259`	unaffected	≤ 5.10.*
`5.15.210`	unaffected	≤ 5.15.*
`6.1.176`	unaffected	≤ 6.1.*
`6.6.143`	unaffected	≤ 6.6.*
`6.12.93`	unaffected	≤ 6.12.*
`6.18.35`	unaffected	≤ 6.18.*
`7.0.12`	unaffected	≤ 7.0.*
`7.1`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[18722c247023035b9e2e2a08a887adec2a9a6e49,9afcb5ea080af13aab37930da627db43bd277665)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,9903a04becf059e44cccf625e23689b7d4378384)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,3d5d81d294ba09487c86bc4ba33dc4a4bec5d215)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,e673889a35a5e4c586d0fae67d8755ca4367d3e2)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,2061d080a013c0ec0a56162cd501fb36d2befc26)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,3c40d381ce04f9575a5d8b542898183c3b4b38dc)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,d630c4b25f36e0e68461561e4c70957ec37fdedd)`	affected	code_commit	—
`[18722c247023035b9e2e2a08a887adec2a9a6e49,b06203ac5f12929d79146bb9f063c2af1d679e63)`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`3.14`	affected	semver	—
`[0,3.14)`	unaffected	semver	—
`[5.10.259,5.11.0)`	unaffected	semver	—
`[5.15.210,5.16.0)`	unaffected	semver	—
`[6.1.176,6.2.0)`	unaffected	semver	—
`[6.6.143,6.7.0)`	unaffected	semver	—
`[6.12.93,6.13.0)`	unaffected	semver	—
`[6.18.35,6.19.0)`	unaffected	semver	—
`[7.0.12,7.1.0)`	unaffected	semver	—
`[7.1,*]`	unaffected	generic	—

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Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

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Advisories

Source	ID	Title
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

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 0.00177.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/2061d080a013c0ec0a56162cd501fb36d2befc26
https://git.kernel.org/stable/c/3c40d381ce04f9575a5d8b542898183c3b4b38dc
https://git.kernel.org/stable/c/3d5d81d294ba09487c86bc4ba33dc4a4bec5d215
https://git.kernel.org/stable/c/9903a04becf059e44cccf625e23689b7d4378384
https://git.kernel.org/stable/c/9afcb5ea080af13aab37930da627db43bd277665
https://git.kernel.org/stable/c/b06203ac5f12929d79146bb9f063c2af1d679e63
https://git.kernel.org/stable/c/d630c4b25f36e0e68461561e4c70957ec37fdedd
https://git.kernel.org/stable/c/e673889a35a5e4c586d0fae67d8755ca4367d3e2
https://lore.kernel.org/linux-cve-announce/2026071904-CVE-2026-63991-8744@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-63991
https://www.cve.org/CVERecord?id=CVE-2026-63991

History

Wed, 22 Jul 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-476
References		https://lore.kernel.org/linux-cve-announce/2026071904-CVE-2026-63991-8744@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-63991 https://www.cve.org/CVERecord?id=CVE-2026-63991
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 `Low`

Sun, 19 Jul 2026 15:30:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt() The skb_clone() function can return NULL if memory allocation fails. send_mcast_pkt() calls skb_clone() without checking the return value, which can lead to a NULL pointer dereference in send_pkt() when it dereferences skb->data. Add a NULL check after skb_clone() and skip the peer if the clone fails.
Title		Bluetooth: 6lowpan: check skb_clone() return value in send_mcast_pkt()
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/2061d080a013c0ec0a56162cd501fb36d2befc26 https://git.kernel.org/stable/c/3c40d381ce04f9575a5d8b542898183c3b4b38dc https://git.kernel.org/stable/c/3d5d81d294ba09487c86bc4ba33dc4a4bec5d215 https://git.kernel.org/stable/c/9903a04becf059e44cccf625e23689b7d4378384 https://git.kernel.org/stable/c/9afcb5ea080af13aab37930da627db43bd277665 https://git.kernel.org/stable/c/b06203ac5f12929d79146bb9f063c2af1d679e63 https://git.kernel.org/stable/c/d630c4b25f36e0e68461561e4c70957ec37fdedd https://git.kernel.org/stable/c/e673889a35a5e4c586d0fae67d8755ca4367d3e2

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-07-19T14:56:11.824Z

Updated: 2026-07-19T14:56:11.824Z

Reserved: 2026-07-19T07:54:57.025Z

Link: CVE-2026-63991

Vulnrichment

No data.

NVD

Status : Awaiting Analysis

Published: 2026-07-19T16:17:37.783

Modified: 2026-07-30T14:51:11.223

Link: CVE-2026-63991

Redhat

Severity : Low

Publid Date: 2026-07-19T00:00:00Z

Links: CVE-2026-63991 - Bugzilla

OpenCVE Enrichment

Updated: 2026-08-04T06:30:05Z

Weaknesses

CWE-476
NULL Pointer Dereference

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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