CVE-2026-98306seg6: set IPSKB_L3SLAVE from IP6SKB_L3SLAVE on IPIP decapsulation
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: seg6: set IPSKB_L3SLAVE from IP6SKB_L3SLAVE on IPIP decapsulation When an SRv6 packet arrives on an interface enslaved to a VRF, vrf_ip6_rcv() sets IP6SKB_L3SLAVE in IP6CB, but decap_and_validate() has never set IPSKB_L3SLAVE in IPCB. The bit stayed clear in the common case, and with CONFIG_IPV6_MIP6 the leftover frag_max_size of a reassembled outer packet could even set it, with no VRF involved. Commit 44930446dde4 ("ipv6: seg6: clear IPv4 control block on IPIP decapsulation") then made the unreliable bit reliably clear. The effect of the missing flag is visible with End.DX4 when a delivery to a local address of the node reaches the socket lookup. For example, a UDP socket bound to the enslaved ingress interface does not receive any of the decapsulated packets, while an unbound socket outside the VRF does. This contradicts Documentation/networking/vrf.rst: by default the scope of an unbound UDP or TCP socket is limited to the default VRF. Set IPSKB_L3SLAVE for IPv4 in decap_and_validate(), which already does the same for IPv6. The socket lookup then matches the decapsulated packet like any other packet received on that enslaved interface. Such a packet matches an unbound UDP or TCP socket only when udp_l3mdev_accept or tcp_l3mdev_accept is set.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 builds before 1d9f5c78903dd25a3556229eb716dd465c5f3573; 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 builds before 72f410616000d21a0a6ec6c93a60301b9c92e95c; from 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 before e4d7c52f15f572608374947c6c802052e1a2fc82; from 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 before 5130afa025c95faa621adf8bac525baeb2b290d2; from 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 before f8fb4738ccef5f9d107845b05734a56352747b1a; from 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 before ddf60220c925b54a1714c4722fdbdb12833232d0; 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 builds before 8c16e1ccc082a3763dfc6bc2d3f658c1a6336f9d; from 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 before 7616242a2b37883f7322aaa1d2bd6cd0fed28315 | CNA record |
References
- https://git.kernel.org/stable/c/1d9f5c78903dd25a3556229eb716dd465c5f3573
- https://git.kernel.org/stable/c/72f410616000d21a0a6ec6c93a60301b9c92e95c
- https://git.kernel.org/stable/c/e4d7c52f15f572608374947c6c802052e1a2fc82
- https://git.kernel.org/stable/c/5130afa025c95faa621adf8bac525baeb2b290d2
- https://git.kernel.org/stable/c/f8fb4738ccef5f9d107845b05734a56352747b1a
- https://git.kernel.org/stable/c/ddf60220c925b54a1714c4722fdbdb12833232d0
- https://git.kernel.org/stable/c/8c16e1ccc082a3763dfc6bc2d3f658c1a6336f9d
- https://git.kernel.org/stable/c/7616242a2b37883f7322aaa1d2bd6cd0fed28315
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.