Skip to content
Fencer Vulns
medium 5.5

CVE-2026-23385 json

netfilter: nf_tables: clone set on flush only

published 2026-03-25 7 mo ago modified 2026-10-30 9 d ago also EUVD-2026-15382

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_tables: clone set on flush only

Syzbot with fault injection triggered a failing memory allocation with GFP_KERNEL which results in a WARN splat:

iter.err WARNING: net/netfilter/nf_tables_api.c:845 at nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845, CPU#0: syz.0.17/5992 Modules linked in: CPU: 0 UID: 0 PID: 5992 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:nft_map_deactivate+0x34e/0x3c0 net/netfilter/nf_tables_api.c:845 Code: 8b 05 86 5a 4e 09 48 3b 84 24 a0 00 00 00 75 62 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 63 6d fa f7 90 <0f> 0b 90 43 +80 7c 35 00 00 0f 85 23 fe ff ff e9 26 fe ff ff 89 d9 RSP: 0018:ffffc900045af780 EFLAGS: 00010293 RAX: ffffffff89ca45bd RBX: 00000000fffffff4 RCX: ffff888028111e40 RDX: 0000000000000000 RSI: 00000000fffffff4 RDI: 0000000000000000 RBP: ffffc900045af870 R08: 0000000000400dc0 R09: 00000000ffffffff R10: dffffc0000000000 R11: fffffbfff1d141db R12: ffffc900045af7e0 R13: 1ffff920008b5f24 R14: dffffc0000000000 R15: ffffc900045af920 FS: 000055557a6a5500(0000) GS:ffff888125496000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb5ea271fc0 CR3: 000000003269e000 CR4: 00000000003526f0 Call Trace: <TASK> __nft_release_table+0xceb/0x11f0 net/netfilter/nf_tables_api.c:12115 nft_rcv_nl_event+0xc25/0xdb0 net/netfilter/nf_tables_api.c:12187 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 blocking_notifier_call_chain+0x6a/0x90 kernel/notifier.c:380 netlink_release+0x123b/0x1ad0 net/netlink/af_netlink.c:761 __sock_release net/socket.c:662 [inline] sock_close+0xc3/0x240 net/socket.c:1455

Restrict set clone to the flush set command in the preparation phase. Add NFT_ITER_UPDATE_CLONE and use it for this purpose, update the rbtree and pipapo backends to only clone the set when this iteration type is used.

As for the existing NFT_ITER_UPDATE type, update the pipapo backend to use the existing set clone if available, otherwise use the existing set representation. After this update, there is no need to clone a set that is being deleted, this includes bound anonymous set.

An alternative approach to NFT_ITER_UPDATE_CLONE is to add a .clone interface and call it from the flush set path.

Patch / fix

  • Linux Linux 5.16, 6.1.191, 6.6.151, 6.12.114, 6.18.17, 6.19.7, 7.0
  • linux Debian 13 6.12.115-2
  • linux Debian 14 6.19.8-1

debian advisories DEBIAN-CVE-2026-23385

  • kernel Azure Linux 3.0 6.6.152.1-1

azure linux advisories AZL-94647

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-23385 updated cvss 5.5

kernel: netfilter: nf_tables: clone set on flush only

  • Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.