UBUNTU-CVE-2026-72248: Medium severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: support IPIP tunnel with direct xmit The combination of IPIP tunnel with direct xmit, eg. bridge device, breaks because no dstentry is provided to check the skb headroom and to set the iph->fragoff field. This leads to invalid dst usage and can trigger a crash in the tunnel transmit path. Fix this by moving dstcache and dstcookie out of the runtime union so that they can be shared by neighbour, xfrm, and direct tunnel flows. For FLOWOFFLOADXMITDIRECT tuples carrying tunnel metadata, preserve route state in these shared fields and release it through the common dst release path. Since dstentry is now available to the three supported xmit modes and dstrelease() already deals with NULL dst, remove the xmit type check in nftflowdstrelease(). Moreover, skip the check if the dst entry is NULL in nfflowdstcheck() which is now the case for the direct xmit case. Based on patch from Rein Wei <n05ec@lzu.edu.cn>.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
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ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
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ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-34.34~24.04.1 - Upgrade
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ubuntu/linux-nvidia-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1024.25~24.04.1 - Upgrade
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ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1012.12~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-34.34.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-34.34 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1007.8 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-nvidia-bosto a version that resolves this vulnerability.Fixed in 7.0.0-2022.23 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1012.12 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 7.0.0-1020.20 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-34.34.1 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-34.34.1
Event History
Frequently Asked Questions
Which systems are most likely to be affected?
The issue is relevant to Ubuntu systems using one of the listed kernel packages and configured with netfilter flowtable direct transmit alongside an IPIP tunnel, for example where direct transmit is used through a bridge device.
What conditions are required to trigger the crash?
The affected path requires the combination of an IPIP tunnel and flowtable direct transmit. In that configuration, missing destination-route state can cause invalid dst_entry use during tunnel transmission and trigger a crash.
Is a default installation known to be affected?
The provided information identifies a configuration-dependent condition involving IPIP tunneling and direct transmit, but does not state that this configuration is enabled by default.
What is the impact if the vulnerable path is reached?
Invalid destination-entry handling can crash the tunnel transmit path. The supplied severity vector rates the issue critical and indicates network-reachable exploitation with no privileges or user interaction required.