TI-2025-15720 Aliases CVE-2025-21768 GHSA-r5gw-qwwg-wx9p

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

LOW 24CWE-401Published 2025-02-27 · Updated 2026-11-05

Key facts

Attack vector: Local
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 2 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-401.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00254 16th percentileScored 2026-11-07

Fix Partial Linux (Linux): 6.1.191, 6.6.160, 6.12.16 +2Red Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Linux	Linux	4.10 and later	6.1.191, 6.6.160, 6.12.16, 6.13.4, 6.14	Patch available	CNA

Linux VendorLinux Affected 4.10 and later Fixed in 6.1.191, 6.6.160, 6.12.16, 6.13.4, 6.14 Patch available CNA

CPE configurations NVD · 2

CPE	Versions	Role	Vendor
cpe:2.3:o:linux:linux_kernel::::::::	4.10 to before 6.12.16; 6.13 to before 6.13.4	Vulnerable	Linux
cpe:2.3:o:linux:linux_kernel:6.14:rc1::::::	6.14 rc1	Vulnerable	Linux

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.10 to before 6.12.16; 6.13 to before 6.13.4 Vulnerable ·Linux
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* Versions 6.14 rc1 Vulnerable ·Linux

Remediation

Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.16, 6.13.4, 6.14

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet

Not affected: 3 products

Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 8

Timeline

2026-10-02 Threatist record created from CVE-2025-21768
2026-10-03 Alias added: GHSA-r5gw-qwwg-wx9p
2026-10-21 Fix available: Linux/[email protected], Linux/Linux@e2ef3fa31353b30bda94358fe5205c141289746d · CNA
2026-10-21 1 new reference · CNA
2026-10-30 Fix available: Linux/Linux@26f0b472ae2a82920e38c7cf41583951046d586a, Linux/[email protected] · CNA
2026-10-30 1 new reference · CNA
2026-11-05 CISA SSVC decision points changed

References

Patch 3

Other 2

TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3

See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences