# CVE-2023-6121: Kernel: nvme: info leak due to out-of-bounds read in nvmet_ctrl_find_get

Status: published. Published: 2023-11-16. Updated: 2026-11-06.

An out-of-bounds read vulnerability was found in the NVMe-oF/TCP subsystem in the Linux kernel. This issue may allow a remote attacker to send a crafted TCP packet, triggering a heap-based buffer overflow that results in kmalloc data being printed and potentially leaked to the kernel ring buffer (dmesg).

## Remediation

- workaround: This flaw can be mitigated by explicitly setting the kernel parameter to restrict unprivileged users from using dmesg:
```
sudo sysctl -w kernel.dmesg_restrict=1
```
To make it persistent between system reboots:
```
echo 'kernel.dmesg_restrict=1' | sudo tee -a /etc/sysctl.conf
``` (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 8 (kernel-rt): ≥ 0:4.18.0-553.rt7.342.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (kernel): ≥ 0:4.18.0-553.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (kernel): ≥ 0:5.14.0-427.13.1.el9_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (kernel): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (kernel-rt): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (kernel-rt): Version range not reported. Source: CNA: redhat
- Siemens / RUGGEDCOM RST2428P: ≥ 0; < * (unaffected, custom). Source: ADP: siemens-SADP
- Siemens / SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family: ≥ 0; < * (unaffected, custom). Source: ADP: siemens-SADP
- Siemens / SCALANCE XCM-/XRM-/XCH-/XRH-300 family: ≥ 0; < * (unaffected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.0; < V3.1.5 (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.0; < V3.1.5 (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 TM MFP - GNU/Linux subsystem: ≥ 0; < V1.1.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.0; < V3.1.5 (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 1.64% as of 2026-11-05; percentile 76.51%

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

- Weaknesses: CWE-125

## Exploit evidence

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

## References

- https://access.redhat.com/errata/RHSA-2024:2394 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2024:2950 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2024:3138 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2023-6121 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2250043 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2024:2394 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/errata/RHSA-2024:2950 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/errata/RHSA-2024:3138 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/security/cve/CVE-2023-6121 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2250043 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://lists.debian.org/debian-lts-announce/2024/01/msg00005.html (ADP: CVE; x_transferred)

- https://cert-portal.siemens.com/productcert/html/ssa-398330.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-265688.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-613116.html (ADP: siemens-SADP)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2023-6121; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2023-6121; retrieved 2026-11-06; source updated Not reported

Revision: 200bb6b30721abed24b1fe5fbf40a571e019eb2578702def9c44b66b6409155c

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