Linux kernel nf_tables catchall activation use-after-free local privilege escalation
CVE-2026-23111 is a use-after-free in the Linux kernel nf_tables subsystem caused by an inverted activity/genmask check in nft_map_catchall_activate(). During abort handling for a failed nftables transaction, catchall map elements that were deactivated earlier should be reactivated. Due to the inverted conditional, the function skips inactive catchall elements and processes active ones, the opposite of the required logic. As a result, when a DELSET operation is aborted, nft_setelem_data_activate() is not invoked for the catchall element. For NFT_GOTO verdict elements, nft_data_hold() is therefore not called to restore the referenced chain's use count. Repeated abort cycles can permanently decrement chain->use until it reaches zero, after which DELCHAIN can free the chain while catchall verdict elements still retain references to it, creating a dangling pointer and use-after-free condition in nf_tables.
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Impact, mitigation & remediation
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Impact
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Mitigation
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Remediation
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Exploits
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No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
16 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Linux kernel local privilege escalation and container escape vulnerability in nf_tables caused by a use-after-free / inverted check, allowing an unprivileged local user to gain root.
A Linux kernel nftables subsystem use-after-free vulnerability that allows unprivileged local attackers to escalate privileges to root, with reliable exploitability demonstrated on affected Debian and Ubuntu distributions.
Unknown
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.