netfilter: flowtable: fix and simplify IP6IP6 tunnel handling

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72442
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:18 UTC
Updated2026-08-17 06:19:11 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: fix and simplify IP6IP6 tunnel handling Fix nf_flow_ip6_tunnel_proto() to use pskb_may_pull() instead of skb_header_pointer() to ensure the outer IPv6 header is in the skb headroom, which is required for subsequent packet processing. Move ctx->offset update inside the IPPROTO_IPV6 conditional block since it should only be adjusted when an IP6IP6 tunnel is actually detected. Simplify the rx path by removing ipv6_skip_exthdr() and checking ip6h->nexthdr directly, as the flowtable fast path only handles simple IP6IP6 encapsulation without extension headers. Drop the tunnel encapsulation limit destination option support from the tx path to match, since the rx path no longer handles extension headers. Remove the encap_limit parameter from nf_flow_offload_ipv6_forward(), nf_flow_tunnel_ip6ip6_push() and nf_flow_tunnel_v6_push(), along with the ipv6_tel_txoption struct and related headroom/MTU adjustments.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.005530000 probability, percentile 0.435850000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d98103575dcdd3a730e0901ab457791a9ac6930c 7f8d816a9aa2729d270418f00c9ef5e85bfc1b31 git Not specified
CNA Linux Linux affected d98103575dcdd3a730e0901ab457791a9ac6930c f4c2d8668d85ed125985da663c824a9c25498257 git Not specified
CNA Linux Linux affected 7.0 Not specified
CNA Linux Linux unaffected 7.0 semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/7f8d816a9aa2729d270418f00c9ef5e85bfc1b31 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f4c2d8668d85ed125985da663c824a9c25498257 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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