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Vulnerability · Published Feb 27, 2025 · Assigned by Linux

CVE-2025-21768net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.3%top 83.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2025-21768
Debian:13linux6.12.16-1DEBIAN-CVE-2025-21768
Debian:14linux6.12.16-1DEBIAN-CVE-2025-21768
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux6.8.0-78.78USN-7703-1
Ubuntu:24.04:LTSlinux6.8.0-78.78UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-aws6.8.0-1035.37USN-7703-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1035.37UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1035.37~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1035.37~22.04.1USN-7703-2
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-azure6.8.0-1034.39UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1015.15~24.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1034.39~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1022.23UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-gcp6.8.0-1036.38USN-7703-2
Ubuntu:24.04:LTSlinux-gcp6.8.0-1036.38UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1015.15~24.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1036.38~22.04.1USN-7703-2
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1036.38~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-gke6.8.0-1032.36UBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-gke6.8.0-1032.36USN-7703-4
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1019.21USN-7703-2
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1019.21UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-26.26~24.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-78.78~22.04.1USN-7703-4
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-78.78~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-ibm6.8.0-1033.33USN-7703-2
Ubuntu:24.04:LTSlinux-ibm6.8.0-1033.33UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1033.33~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1033.33~22.04.1USN-7703-2
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-78.78.1USN-7703-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-78.78.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1014.15~24.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-78.78.1~22.04.1USN-7703-1
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-78.78.1~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1035.38USN-7703-4
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1035.38UBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-nvidia-6.116.11.0-1010.10UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1035.38~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1035.38~22.04.1USN-7703-4
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1035.38.1USN-7703-4
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1035.38.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1009.9UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1022.22UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-oracle6.8.0-1032.33UBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-oracle6.8.0-1032.33USN-7703-3
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1032.33~22.04.1USN-7703-3
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1032.33~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-raspi6.8.0-1035.39UBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-raspi6.8.0-1035.39USN-7703-4
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-78.78~22.04.1UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-21768
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1017.18UBUNTU-CVE-2025-21768
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2025-21768

Affected products (as reported)

VendorProductVersions
Linux Linux 6c8702c60b88651072460f3f4026c7dfe2521d12 – before 26f0b472ae2a82920e38c7cf41583951046d586a6c8702c60b88651072460f3f4026c7dfe2521d12 – before e2ef3fa31353b30bda94358fe5205c141289746d6c8702c60b88651072460f3f4026c7dfe2521d12 – before 5ab11a4e219e93b8b31a27f8ec98d42afadd8b7a6c8702c60b88651072460f3f4026c7dfe2521d12 – before 4c0f200c7d06fedddde82209c099014d63f4a6c06c8702c60b88651072460f3f4026c7dfe2521d12 – before 92191dd1073088753821b862b791dcc83e558e07
Linux Linux 4.10

References