Unknown

CVE-2026-98306 — seg6: set IPSKB_L3SLAVE from IP6SKB_L3SLAVE on IPIP decapsulation

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.

Published Oct 6, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+1

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.18%

ahead of 7% of scored CVEs · Oct 14, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < 1d9f5c78903dd25a3556229eb716dd465c5f3573≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < 72f410616000d21a0a6ec6c93a60301b9c92e95c≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < e4d7c52f15f572608374947c6c802052e1a2fc82≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < 5130afa025c95faa621adf8bac525baeb2b290d2≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < f8fb4738ccef5f9d107845b05734a56352747b1a≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < ddf60220c925b54a1714c4722fdbdb12833232d0≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < 8c16e1ccc082a3763dfc6bc2d3f658c1a6336f9d≥ 891ef8dd2a8d14e4e73a81dcdb135b574c57f556 and < 7616242a2b37883f7322aaa1d2bd6cd0fed28315 and 1 more version 4.14	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.18%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 13, 2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Oct 6, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

8 on the record

git.kernel.org/stable/c/8c16e1ccc082a3763dfc6bc2d3f658c1a6336f9d
NIST National Vulnerability Database
git.kernel.org/stable/c/72f410616000d21a0a6ec6c93a60301b9c92e95c
NIST National Vulnerability Database
git.kernel.org/stable/c/7616242a2b37883f7322aaa1d2bd6cd0fed28315
NIST National Vulnerability Database
git.kernel.org/stable/c/1d9f5c78903dd25a3556229eb716dd465c5f3573
NIST National Vulnerability Database
git.kernel.org/stable/c/f8fb4738ccef5f9d107845b05734a56352747b1a
NIST National Vulnerability Database
git.kernel.org/stable/c/e4d7c52f15f572608374947c6c802052e1a2fc82
NIST National Vulnerability Database
git.kernel.org/stable/c/ddf60220c925b54a1714c4722fdbdb12833232d0
NIST National Vulnerability Database
git.kernel.org/stable/c/5130afa025c95faa621adf8bac525baeb2b290d2
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 6h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 6h
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-98306 is "seg6: set IPSKB_L3SLAVE from IP6SKB_L3SLAVE on IPIP decapsulation", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.18% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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