CVE-2026-23278
Published: 20 March 2026
Summary
CVE-2026-23278 is a high-severity an unspecified weakness vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 4.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and RA-5 (Vulnerability Monitoring and Scanning).
Deeper analysis
CVE-2026-23278 is a vulnerability in the Linux kernel's netfilter nf_tables subsystem. It occurs during transaction processing when multiple catchall elements exist—one live and one pending in a new batch—and the map holding them is being removed. The issue arises because the code does not walk all pending catchall elements, toggling only the first viable candidate instead. This leads to a kernel warning in nft_data_release, followed by failures in __nft_set_elem_destroy, nf_tables_abort_release, nf_tables_abort, and nfnetlink_rcv_batch.
A local attacker with low privileges (PR:L) can exploit this vulnerability with low complexity (AC:L) and no user interaction (UI:N). Successful exploitation results in high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), as indicated by the CVSS v3.1 base score of 7.8. The unchanged scope (S:U) suggests the attacker can trigger the abort condition in nf_tables during netfilter rule or map manipulations, potentially leading to kernel crashes or memory corruption.
Mitigation is provided through kernel patches in the stable trees, as detailed in the referenced commits: 77c26b5056d693ffe5e9f040e946251cdb55ae55, 7cb9a23d7ae40a702577d3d8bacb7026f04ac2a9, de47a88c6b807910f05703fb6605f7efdaa11417, and eb0948fa13298212c5f8b30ee48efdae4389ab09. Security practitioners should update to kernels incorporating these fixes to ensure proper handling of all catchall elements during map destruction.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-13614
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: always walk all pending catchall elements During transaction processing we might have more than one catchall element: 1 live catchall element and 1 pending element that is coming…
more
as part of the new batch. If the map holding the catchall elements is also going away, its required to toggle all catchall elements and not just the first viable candidate. Otherwise, we get: WARNING: ./include/net/netfilter/nf_tables.h:1281 at nft_data_release+0xb7/0xe0 [nf_tables], CPU#2: nft/1404 RIP: 0010:nft_data_release+0xb7/0xe0 [nf_tables] [..] __nft_set_elem_destroy+0x106/0x380 [nf_tables] nf_tables_abort_release+0x348/0x8d0 [nf_tables] nf_tables_abort+0xcf2/0x3ac0 [nf_tables] nfnetlink_rcv_batch+0x9c9/0x20e0 [..]
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel memory corruption/crash in nf_tables enables privilege escalation from low-privileged user via crafted netfilter transactions.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates CVE-2026-23278 by requiring timely patching of the Linux kernel to fix improper handling of all pending catchall elements during nf_tables map destruction.
Vulnerability scanning identifies Linux kernel versions affected by CVE-2026-23278, enabling prioritization for remediation.
System monitoring of kernel logs detects indicators of exploitation such as warnings in nft_data_release during nf_tables transaction aborts.