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Linux Kernel CVE-2026-72249

| EUVDEUVD-2026-59148 CRITICAL
2026-08-15 416baaa9-dc9f-4396-8d5f-8c081fb06d67 GHSA-3xpj-q99r-5475
Information Disclosure Linux Red Hat Suse
Critical
Disputed · 9.8 Vendor: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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Severity by source

Sources disagree (Medium–Critical)
Vendor (416baaa9-dc9f-4396-8d5f-8c081fb06d67) PRIMARY
9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
4.8 MEDIUM

Triggered over the network but only when a non-default flowtable IPIP offload path is configured and hit (AC:H); impact limited to frag_off info leak (C:L) and possible headroom-driven instability (A:L), no integrity or code execution.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
SUSE
7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Red Hat
7.0 MEDIUM
qualitative

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorVendor: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

Lifecycle Timeline

4
Analysis Generated
Aug 17, 2026 - 07:56 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
9.8 (CRITICAL)
CVE Published
Aug 15, 2026 - 06:21 cve.org
CRITICAL 9.8
CVE Published
Aug 15, 2026 - 06:21 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

netfilter: flowtable: use dst in this direction when pushing IPIP header

When pushing the IPIP header, the route of the other direction is used to calculate the headroom, use the route in this direction. Accessing the other tuple to set the IP source and destination is fine because this tuple does not provide such information to avoid storing redundant information. However, this tuple already provides the dst for this direction, this went unnoticed because this bug affects headroom and iph->frag_off only at this stage.

AnalysisAI

Incorrect route selection in the Linux kernel's netfilter flowtable IPIP-encapsulation offload path causes the headroom and IP fragment-offset (iph->frag_off) to be computed from the reverse-direction dst instead of the current direction when pushing the IPIP header. Affecting kernel 6.19 and development branches through the 7.x line, the flaw can lead to malformed encapsulated packets and potential memory/headroom mishandling in the fast-path offload; it is tagged as information disclosure. The input CVSS of 9.8 (RCE-grade) is a CNA auto-score that overstates a config-dependent packet-handling bug, and EPSS is low at 0.20% (10th percentile) with no public exploit or KEV listing.

Technical ContextAI

The vulnerability lives in netfilter's software flowtable, the connection-tracking fast path that offloads established flows to bypass the normal per-packet routing. When a flow is offloaded with IP-in-IP (IPIP) tunnel encapsulation, the code must add an outer IPv4 header and reserve enough skb headroom for it. The bug is that it referenced the dst (route) cached for the opposite tuple/direction to size the headroom and derive iph->frag_off, rather than the dst for the direction actually being transmitted. Reading the reverse tuple only for IP source/destination is intentional (that data is stored once to avoid redundancy), but the transmit dst is direction-specific and was mistakenly cross-wired. No CWE was assigned by the CNA; the defect is best characterized as an incorrect resource/pointer selection leading to wrong buffer-headroom calculation and an incorrect fragmentation field on emitted packets.

RemediationAI

Apply the upstream kernel fix: update to a stable release containing the patch (indicated as 7.1.5 or 7.2-rc3, or your distribution's backport of commits ecb78fbb03d3f86e2e93767875e273308086a424 / c328b90c17fc5fa7786503695152880b2afb9326 from https://git.kernel.org/stable/). Because references point to stable-tree commits rather than a single tagged consumer release, confirm the exact patched build with your distribution's advisory before deploying. As a compensating control until patched, disable IPIP tunnel offload in the netfilter flowtable path - either remove the 'flow offload' rule from the affected nftables flowtable/chain or avoid IPIP encapsulation on offloaded flows; the trade-off is loss of fast-path forwarding performance for those flows, which fall back to the normal (correct) routing path. Restricting who can load nftables/flowtable configuration (CAP_NET_ADMIN) further limits exposure since the vulnerable path only activates on operator-defined offload rules.

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Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 16.0 Not-Affected

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CVE-2026-72249 vulnerability details – vuln.today
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