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

net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels

Some lwtunnels have a dst cache for post-transformation dst.
If the packet destination did not change we may end up recording
a reference to the lwtunnel in its own cache, and the lwtunnel
state will never be freed.

Discovered by the ioam6.sh test, kmemleak was recently fixed
to catch per-cpu memory leaks. I'm not sure if rpl and seg6
can actually hit this, but in principle I don't see why not.
Published: 2025-02-27
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2025-5155 In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache, and the lwtunnel state will never be freed. Discovered by the ioam6.sh test, kmemleak was recently fixed to catch per-cpu memory leaks. I'm not sure if rpl and seg6 can actually hit this, but in principle I don't see why not.
Ubuntu USN Ubuntu USN USN-7521-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7521-2 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7521-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7703-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7703-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7703-3 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-7703-4 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7719-1 Linux kernel (Raspberry Pi Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7737-1 Linux kernel (Azure) vulnerabilities
History

Tue, 28 Oct 2025 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel

Sat, 03 May 2025 06:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'}

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'}


Wed, 30 Apr 2025 15:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-401
Metrics 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'}

cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H'}


Fri, 28 Feb 2025 02:00:00 +0000

Type Values Removed Values Added
References
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


Thu, 27 Feb 2025 02:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache, and the lwtunnel state will never be freed. Discovered by the ioam6.sh test, kmemleak was recently fixed to catch per-cpu memory leaks. I'm not sure if rpl and seg6 can actually hit this, but in principle I don't see why not.
Title net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T21:06:02.120Z

Reserved: 2024-12-29T08:45:45.762Z

Link: CVE-2025-21768

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2025-02-27T03:15:17.480

Modified: 2025-10-28T20:28:41.980

Link: CVE-2025-21768

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-02-27T00:00:00Z

Links: CVE-2025-21768 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses