Privilege escalation via netfilter array-offset underflow
Published Sep 25, 2023 · Updated Aug 6, 2026
Out-of-bounds write in the Linux kernel netfilter subsystem in Red Hat Enterprise Linux allows local users to crash or escalate privileges. The missing IP_SET_HASH_WITH_NET0 macro in ip_set_hash_netportnet selects the wrong CIDR_POS(c), underflows the h->nets offset, and accesses slab memory out of bounds. Exploitation requires local low-privileged access and can interrupt the host or corrupt kernel memory to gain elevated privileges.
Summary
What happened
Out-of-bounds write in the Linux kernel netfilter subsystem in Red Hat Enterprise Linux allows local users to crash or escalate privileges. The missing IP_SET_HASH_WITH_NET0 macro in ip_set_hash_netportnet selects the wrong CIDR_POS(c), underflows the h->nets offset, and accesses slab memory out of bounds. Exploitation requires local low-privileged access and can interrupt the host or corrupt kernel memory to gain elevated privileges.
The record
- CVE
- CVE-2023-42753
- Published
- Sep 25, 2023
- Updated
- Aug 6, 2026
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 25, 2023CVE publishedPublication date reported by the CVE source.
- Aug 6, 2026Record 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?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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