Bug 2449570 (CVE-2026-23278)

Summary: CVE-2026-23278 kernel: netfilter: nf_tables: always walk all pending catchall elements
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's netfilter subsystem, specifically within the nf_tables component. This vulnerability occurs during transaction processing when the system incorrectly handles multiple pending catchall elements, particularly when the associated map is being removed. This can lead to a kernel warning and system instability, potentially causing a Denial of Service (DoS) for the affected system.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-03-20 09:03:15 UTC 
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 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 [..]
Comment 1 Alexander B 2026-03-20 12:20:44 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026032036-CVE-2026-23278-4dcc@gregkh/T