# CVE-2026-46323: net: gro: don't merge zcopy skbs

Status: published. Published: 2026-06-09. Updated: 2026-11-10.

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.

## Remediation

- fix: RHSA-2026:47727: Red Hat OpenShift Container Platform 4.17

RHSA-2026:44230: Red Hat OpenShift Container Platform 4.18

RHSA-2026:44231: Red Hat OpenShift Container Platform 4.19

RHSA-2026:44259: Red Hat OpenShift Container Platform 4.20

RHSA-2026:44262: Red Hat OpenShift Container Platform 4.21

RHSA-2026:27731: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)

RHSA-2026:44270: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10)

RHSA-2026:27735: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)

RHSA-2026:27708: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)

RHSA-2026:36018: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9)

RHSA-2026:62642: Red Hat Enterprise Linux BaseOS (v. 10)

RHSA-2026:62639: Red Hat Enterprise Linux BaseOS E4S (v.9.4)

RHSA-2026:62641: Red Hat Enterprise Linux BaseOS EUS (v.9.6)

RHSA-2026:62640: Red Hat Enterprise Linux BaseOS (v. 9) (source: ADP: redhat-SADP)
- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. (source: ADP: redhat-SADP)

## Affected products and versions

- Linux / Linux: ≥ 753f1ca4e1e50248a1b760c9774d6d6b354562cc; < 3c6cc9f2ca65b6dd61b1af75452dc0e1cd0aad8d (affected, git); ≥ 753f1ca4e1e50248a1b760c9774d6d6b354562cc; < 1f9c828556416fbe3f49386708ce999fc4d4da06 (affected, git); ≥ 753f1ca4e1e50248a1b760c9774d6d6b354562cc; < 479084ae0e1d9cb7929cb4298d35623de189f80a (affected, git); ≥ 753f1ca4e1e50248a1b760c9774d6d6b354562cc; < e334cbf3388fd9334503a778a82d9e9f14dd2f71 (affected, git); ≥ 753f1ca4e1e50248a1b760c9774d6d6b354562cc; < 44bea2032af0425e4ce6d26a8af0ede79db49ec1 (affected, git); ≥ 753f1ca4e1e50248a1b760c9774d6d6b354562cc; < 4db79a322db8c97f7b73b8a347395ef4d685eb40 (affected, git). Source: CNA: Linux
- Linux / Linux: 6.0 (affected); ≥ 0; < 6.0 (unaffected, semver); ≥ 6.1.176; ≤ 6.1.* (unaffected, semver); ≥ 6.6.142; ≤ 6.6.* (unaffected, semver); ≥ 6.12.92; ≤ 6.12.* (unaffected, semver); ≥ 6.18.34; ≤ 6.18.* (unaffected, semver); ≥ 7.0.11; ≤ 7.0.* (unaffected, semver); ≥ 7.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Red Hat / Red Hat Enterprise Linux 10 (kernel): ≥ 0:6.12.0-211.38.1.el10_2; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support (kernel): ≥ 0:6.12.0-55.82.1.el10_0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (kernel): ≥ 0:5.14.0-687.22.1.el9_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (kernel): ≥ 0:5.14.0-427.132.1.el9_4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (kernel): ≥ 0:5.14.0-570.123.1.el9_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4.17 (rhcos): ≥ 417.94.202607240132-0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4.18 (rhcos): ≥ 418.94.202607211754-0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4.19 (rhcos): ≥ 4.19.9.6.202607220857-0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4.20 (rhcos): ≥ 4.20.9.6.202607221038-0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4.21 (rhcos): ≥ 4.21.9.6.202607221317-0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 6 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 (kernel-rt): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (kernel-rt): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (kernel-rt): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux for NVIDIA 26 (kernel): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: ADP: redhat-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 TM MFP - GNU/Linux subsystem: ≥ 0; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: CNA: Linux

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H; source: ADP: redhat-SADP

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-09; percentile 3.16%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-123, CWE-416

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/3c6cc9f2ca65b6dd61b1af75452dc0e1cd0aad8d (CNA: Linux)

- https://git.kernel.org/stable/c/1f9c828556416fbe3f49386708ce999fc4d4da06 (CNA: Linux)

- https://git.kernel.org/stable/c/479084ae0e1d9cb7929cb4298d35623de189f80a (CNA: Linux)

- https://git.kernel.org/stable/c/e334cbf3388fd9334503a778a82d9e9f14dd2f71 (CNA: Linux)

- https://git.kernel.org/stable/c/44bea2032af0425e4ce6d26a8af0ede79db49ec1 (CNA: Linux)

- https://git.kernel.org/stable/c/4db79a322db8c97f7b73b8a347395ef4d685eb40 (CNA: Linux)

- https://access.redhat.com/security/cve/CVE-2026-46323 (ADP: redhat-SADP; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2479832 (ADP: redhat-SADP; issue-tracking, x_refsource_REDHAT)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46323.json (ADP: redhat-SADP; x_sadp-csaf-vex)

- https://access.redhat.com/errata/RHSA-2026:47727 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:44230 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:44231 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:44259 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:44262 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:27731 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:44270 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:27735 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:27708 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:36018 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:62642 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:62639 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:62641 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:62640 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-46323; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-46323; retrieved 2026-11-10; source updated Not reported

Revision: 27ea0ddfb5daf45d147eb6ef98e1bed4fe253f91a171c63aae2da4fbade9f81c

Canonical: https://y2.dev/cve/CVE-2026-46323

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