Kernel crash or disclosure via unchecked xt_u32 sizes
Published Oct 9, 2023 · Updated Nov 8, 2025
Out-of-bounds read in the Netfilter xt_u32 module in Red Hat Enterprise Linux 8 allows local users with CAP_NET_ADMIN to crash the kernel. The xt_u32 match registration lacked a checkentry validator, so oversized ntests, nnums, or nvalues fields drove reads beyond fixed arrays. Exploitation requires CAP_NET_ADMIN; the bounded outcomes are kernel memory disclosure or a system crash, with no integrity impact reported.
Summary
What happened
Out-of-bounds read in the Netfilter xt_u32 module in Red Hat Enterprise Linux 8 allows local users with CAP_NET_ADMIN to crash the kernel. The xt_u32 match registration lacked a checkentry validator, so oversized ntests, nnums, or nvalues fields drove reads beyond fixed arrays. Exploitation requires CAP_NET_ADMIN; the bounded outcomes are kernel memory disclosure or a system crash, with no integrity impact reported.
The record
- CVE
- CVE-2023-39192
- Published
- Oct 9, 2023
- Updated
- Nov 8, 2025
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 8
- Classifications
- CWE-125, T1499
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Oct 9, 2023CVE publishedPublication date reported by the CVE source.
- Nov 8, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Linux kernel Netfilter xt_u32 proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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