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Linux Kernel CVE-2026-46323

| EUVDEUVD-2026-35413 HIGH
Write-what-where Condition (CWE-123)
2026-06-09 Linux GHSA-hf4r-hm8m-w52j
Information Disclosure Linux
7.8
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
7.0 HIGH

Local kernel UAF reachable only by a local user driving a zero-copy + GRO race, so AV:L/PR:L/UI:N with AC:H for the race; successful exploitation yields full kernel CIA impact.

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

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

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

Lifecycle Timeline

5
Analysis Generated
Jun 14, 2026 - 06:34 vuln.today
CVSS changed
Jun 14, 2026 - 06:22 NVD
7.8 (HIGH)
Patch available
Jun 09, 2026 - 14:01 EUVD
CVE Published
Jun 09, 2026 - 12:11 cve.org
HIGH 7.8
CVE Published
Jun 09, 2026 - 12:11 nvd
UNKNOWN (no severity yet)

DescriptionCVE.org

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

net: gro: don't merge zcopy skbs

skb_gro_receive() can currently copy frags between the source and GRO skb, without checking the zerocopy status, and in particular the SKBFL_MANAGED_FRAG_REFS flag.

When SKBFL_MANAGED_FRAG_REFS is set, the skb doesn't hold a reference on the pages in shinfo->frags. Appending those frags to another skb's frags without fixing up the page refcount can lead to UAF.

When either the last skb in the GRO chain (the one we would append frags to) or the source skb is zerocopy, don't merge the skbs.

AnalysisAI

Use-after-free in the Linux kernel's Generic Receive Offload (GRO) networking path allows local attackers to corrupt kernel memory and potentially achieve privilege escalation or denial of service. The flaw stems from skb_gro_receive() merging fragment lists between socket buffers without honoring the SKBFL_MANAGED_FRAG_REFS zero-copy flag, leaving page refcounts inconsistent. No public exploit identified at time of analysis, and EPSS exploitation probability is very low at 0.02% (5th percentile).

Technical ContextAI

The bug lives in the Linux kernel's GRO subsystem (net/core), which aggregates incoming network packets into larger skbs before they are passed up the stack to improve throughput. When an skb is marked with SKBFL_MANAGED_FRAG_REFS, its shinfo->frags pages are not held with a normal page reference - the lifetime is managed by the originating zero-copy mechanism (commonly MSG_ZEROCOPY / io_uring send-zc or AF_XDP-style paths). skb_gro_receive() copied frags between the source skb and the GRO skb without consulting that flag, so the receiving skb ended up with frag pointers it never refcounted, classic use-after-free territory once the original owner releases the pages. The CWE is not assigned, but this is a UAF (CWE-416) introduced by commit 753f1ca4e1e5 (the MANAGED_FRAG_REFS infrastructure landed in Linux 6.0) and fixed by refusing to merge whenever either side of the merge is zero-copy.

RemediationAI

Vendor-released patch: upgrade to Linux 6.6.142, 6.12.92, 7.0.11, or 7.1-rc5 (or later) which include the fix that makes skb_gro_receive() refuse to merge whenever the last GRO chain skb or the source skb has zero-copy frags. Direct stable commits are available at https://git.kernel.org/stable/c/1f9c828556416fbe3f49386708ce999fc4d4da06, https://git.kernel.org/stable/c/479084ae0e1d9cb7929cb4298d35623de189f80a, https://git.kernel.org/stable/c/e334cbf3388fd9334503a778a82d9e9f14dd2f71, https://git.kernel.org/stable/c/44bea2032af0425e4ce6d26a8af0ede79db49ec1, and https://git.kernel.org/stable/c/4db79a322db8c97f7b73b8a347395ef4d685eb40 for self-built kernels; distribution users should apply the vendor errata for their tracked stream. As a temporary compensating control on systems that cannot reboot immediately, disable GRO on the affected interfaces with 'ethtool -K <iface> gro off' - note this can reduce network throughput and increase CPU usage on high-traffic NICs, so measure before deploying broadly. Restricting local user access (no untrusted shell or container workloads on the host) also reduces practical exposure given the AV:L vector.

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Vendor StatusVendor

SUSE

Severity: Important
Product Status
openSUSE Tumbleweed Fixed
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected

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CVE-2026-46323 vulnerability details – vuln.today
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