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CVE-2023-4128

Publication date 10 August 2023

Last updated 24 July 2024

Ubuntu priority

High

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

** REJECT ** DO NOT USE THIS CVE RECORD. ConsultIDs: CVE-2023-4206, CVE-2023-4207, CVE-2023-4208. Reason: This record is a duplicate of CVE-2023-4206, CVE-2023-4207, CVE-2023-4208. Notes: All CVE users should reference CVE-2023-4206, CVE-2023-4207, CVE-2023-4208 instead of this record. All references and descriptions in this record have been removed to prevent accidental usage.

From the Ubuntu Security Team

It was discovered that some network classifier implementations in the Linux kernel contained use-after-free vulnerabilities. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Read the notes from the security team

Why is this CVE high priority?

By using unprivileged user namespaces, this can be exploited to achieve local privilege escalation.

Learn more about Ubuntu priority

Mitigation

If not needed, disable the ability for unprivileged users to create namespaces. To do this temporarily, do: sudo sysctl -w kernel.unprivileged_userns_clone=0 To disable across reboots, do: echo kernel.unprivileged_userns_clone=0 | \ sudo tee /etc/sysctl.d/99-disable-unpriv-userns.conf

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Notes

rodrigo-zaiden

the fix commits can be found split in CVE-2023-4206, CVE-2023-4207 and CVE-2023-4208. these 3 are likely to be marked as duplicated.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
linux

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

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Other references