CVE-2026-64580 - Vulnerability Details

- xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()

Description

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

xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()

On the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst()
releases the device reference with netdev_put() but leaves
xdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev)
again, so the same net_device reference is released twice, underflowing
its refcount (ref_tracker WARNING + "unregister_netdevice: waiting for
<dev> to become free").

Clear xdst->u.dst.dev after the netdev_put(), the same way the XFRM
device-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in
net/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error.

ref_tracker: reference already released.
ref_tracker: allocated in:
xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86)
...
udpv6_sendmsg (net/ipv6/udp.c:1696)
...
ref_tracker: freed in:
xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90)
...
WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780
dst_destroy (net/core/dst.c:115)
rcu_core
handle_softirqs
...

Published: 2026-08-05

Score: 7.8 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

A flaw in the Linux kernel’s IPv6 XFRM implementation causes a double release of a device reference. On the error path where in6_dev_get returns NULL, xfrm6_fill_dst releases the device reference with netdev_put but leaves the underlying device pointer in xdst->u.dst.dev set. When dst_destroy later calls netdev_put on the same pointer, the reference counter underflows and ref_tracker emits a warning about a released reference.

Affected Systems

All builds of the Linux kernel that include the IPv6 XFRM code are potentially affected; no specific version range is indicated in the CVE record.

Risk and Exploitability

The CVSS score of 7.8 indicates high severity, and the EPSS score of <1% suggests a low probability of exploitation. The vulnerability is not listed in the CISA KEV catalog. No explicit attack vector or exploitation method is provided in the CVE description.

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
`84c4a9dfbf430861e7588d95ae3ff61535dca351`	affected	< 97e032e5733e49471fb73de117ea2ac1ac7c479a
`84c4a9dfbf430861e7588d95ae3ff61535dca351`	affected	< df6856c2dda9187601d29b5fbd7a81b3b178cedf
`84c4a9dfbf430861e7588d95ae3ff61535dca351`	affected	< 43de8a49335e611adb271bbd52e84dfbc11fc185
`84c4a9dfbf430861e7588d95ae3ff61535dca351`	affected	< ff636d7b7cba6dea82ecf580415ea57f2c1a11b6
`84c4a9dfbf430861e7588d95ae3ff61535dca351`	affected	< e078da1b4e11390cff3201c19a9a1fe70c5b934f
`84c4a9dfbf430861e7588d95ae3ff61535dca351`	affected	< 136992de9bb91871084ae52d172610541c76e4d2
`a7e22d0c0e81dde129a51ee413644124f4b59954`	affected	—
`01b0d887f67a388fb2a658ee2bdd74e5ba146818`	affected	—
`a98124aac0b5adc5de8ae54f11322781cb4d85c3`	affected	—
`e27b7bee743d921f037b1da6f071237345bef7c1`	affected	—
`3.0.79`	affected	< 3.1
`3.2.46`	affected	< 3.3
`3.4.46`	affected	< 3.5
`3.9.3`	affected	< 3.10

Linux

affected

Version	Status	Constraints
`3.10`	affected	—
`0`	unaffected	< 3.10
`6.1.183`	unaffected	≤ 6.1.*
`6.6.148`	unaffected	≤ 6.6.*
`6.12.101`	unaffected	≤ 6.12.*
`6.18.42`	unaffected	≤ 6.18.*
`7.1.6`	unaffected	≤ 7.1.*
`7.2`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[84c4a9dfbf430861e7588d95ae3ff61535dca351,df6856c2dda9187601d29b5fbd7a81b3b178cedf)`	affected	code_commit	—
`[84c4a9dfbf430861e7588d95ae3ff61535dca351,43de8a49335e611adb271bbd52e84dfbc11fc185)`	affected	code_commit	—
`[84c4a9dfbf430861e7588d95ae3ff61535dca351,ff636d7b7cba6dea82ecf580415ea57f2c1a11b6)`	affected	code_commit	—
`[84c4a9dfbf430861e7588d95ae3ff61535dca351,e078da1b4e11390cff3201c19a9a1fe70c5b934f)`	affected	code_commit	—
`[84c4a9dfbf430861e7588d95ae3ff61535dca351,136992de9bb91871084ae52d172610541c76e4d2)`	affected	code_commit	—
`a7e22d0c0e81dde129a51ee413644124f4b59954`	affected	code_commit	—
`01b0d887f67a388fb2a658ee2bdd74e5ba146818`	affected	code_commit	—
`a98124aac0b5adc5de8ae54f11322781cb4d85c3`	affected	code_commit	—
`e27b7bee743d921f037b1da6f071237345bef7c1`	affected	code_commit	—
`[3.0.79,3.1)`	affected	semver	—
`[3.2.46,3.3)`	affected	semver	—
`[3.4.46,3.5)`	affected	semver	—
`[3.9.3,3.10)`	affected	semver	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`3.10`	affected	semver	—
`[0,3.10)`	unaffected	semver	—
`[6.6.148,6.7.0)`	unaffected	semver	—
`[6.12.101,6.13.0)`	unaffected	semver	—
`[6.18.42,6.19.0)`	unaffected	semver	—
`[7.1.6,7.2.0)`	unaffected	semver	—
`[7.2-rc4,*]`	unaffected	semver	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Apply a kernel patch that clears the xdst->u.dst.dev reference on error in xfrm6_fill_dst
Upgrade to a Linux kernel version that includes the fix
After applying the patch, verify that no ref_tracker warnings are logged

Generated by OpenCVE AI on August 8, 2026 at 19:50 UTC.

Tracking

Sign in to view the affected projects.

Advisories

Source	ID	Title
Debian DLA	DLA-4745-1	linux-6.12 security update
Debian DSA	DSA-6415-1	linux security update

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

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 0.0012.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/136992de9bb91871084ae52d172610541c76e4d2
https://git.kernel.org/stable/c/43de8a49335e611adb271bbd52e84dfbc11fc185
https://git.kernel.org/stable/c/97e032e5733e49471fb73de117ea2ac1ac7c479a
https://git.kernel.org/stable/c/df6856c2dda9187601d29b5fbd7a81b3b178cedf
https://git.kernel.org/stable/c/e078da1b4e11390cff3201c19a9a1fe70c5b934f
https://git.kernel.org/stable/c/ff636d7b7cba6dea82ecf580415ea57f2c1a11b6

History

Wed, 19 Aug 2026 16:45:00 +0000

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/97e032e5733e49471fb73de117ea2ac1ac7c479a

Sat, 08 Aug 2026 18:15:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-415 CWE-416

Sat, 08 Aug 2026 15:15:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`

Wed, 05 Aug 2026 09:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-415 CWE-416

Wed, 05 Aug 2026 08:15:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst() On the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst() releases the device reference with netdev_put() but leaves xdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev) again, so the same net_device reference is released twice, underflowing its refcount (ref_tracker WARNING + "unregister_netdevice: waiting for <dev> to become free"). Clear xdst->u.dst.dev after the netdev_put(), the same way the XFRM device-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in net/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error. ref_tracker: reference already released. ref_tracker: allocated in: xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86) ... udpv6_sendmsg (net/ipv6/udp.c:1696) ... ref_tracker: freed in: xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90) ... WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780 dst_destroy (net/core/dst.c:115) rcu_core handle_softirqs ...
Title		xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()
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/136992de9bb91871084ae52d172610541c76e4d2 https://git.kernel.org/stable/c/43de8a49335e611adb271bbd52e84dfbc11fc185 https://git.kernel.org/stable/c/df6856c2dda9187601d29b5fbd7a81b3b178cedf https://git.kernel.org/stable/c/e078da1b4e11390cff3201c19a9a1fe70c5b934f https://git.kernel.org/stable/c/ff636d7b7cba6dea82ecf580415ea57f2c1a11b6

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-08-05T08:09:34.946Z

Updated: 2026-08-19T16:29:07.038Z

Reserved: 2026-07-19T15:36:31.798Z

Link: CVE-2026-64580

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-08-05T08:16:38.027

Modified: 2026-08-19T17:20:18.147

Link: CVE-2026-64580

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-08-08T20:00:04Z

Weaknesses

No weakness.

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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