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CVE Record

CVE-2026-23385: netfilter: nf_tables: clone set on flush only

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.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

A Linux kernel nftables flaw can trigger an internal warning when memory allocation fails during ruleset cleanup. The available record does not establish data compromise, privilege escalation, remote reachability, or service disruption. Impact and severity remain insufficiently characterized.

Executive priority

Treat this as a patch-verification item, not an emergency incident, unless vendor analysis identifies stronger impact. Promptly determine affected kernel deployments and schedule supported updates. Escalate if kernel warnings, instability, or new exploitation evidence appears.

Technical view

Fault injection caused allocation failure and a WARN in nft_map_deactivate during nftables table release. The correction restricts set cloning to flush-set preparation, introduces NFT_ITER_UPDATE_CLONE, and adjusts rbtree and pipapo handling to avoid unnecessary cloning during deletion.

Likely exposure

Exposure is limited to Linux kernels identified as affected in the CVE record and code paths using nf_tables. Distribution backports may change actual status. The sources do not specify required privileges, configurations, or whether the issue is remotely reachable.

Exploitation context

The CVE is not listed as KEV, and the supplied sources provide no evidence of active exploitation or a public weaponized exploit. The observed failure came from syzbot fault injection, which does not by itself demonstrate practical exploitation.

Researcher notes

The reproducer involved GFP_KERNEL allocation failure followed by a warning during netlink socket closure and table release. The patch changes cloning semantics for flush versus delete/update paths. The source bundle lacks CVSS, CWE classification, concrete security impact, exploit prerequisites, and reproducibility details suitable for risk quantification.

Mitigation direction

  • Apply a vendor-supported kernel containing the referenced fix or an equivalent distribution backport.
  • Review Linux distribution advisories and package changelogs for CVE-2026-23385 coverage.
  • Prioritize systems using nftables after confirming their installed kernels are affected.
  • Use vendor guidance for interim controls if an updated kernel is unavailable.

Validation and detection

  • Inventory running kernel versions across Linux hosts and compare them with vendor CVE status.
  • Check package changelogs for CVE-2026-23385 or the referenced stable-kernel commits.
  • Confirm updated hosts booted into the remediated kernel, not merely installed it.
  • Monitor kernel logs for nf_tables warnings while avoiding fault-injection testing on production systems.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-23385 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux744dc9a47a8458ed49becd6123a092c7dae82b8b, 3f1d886cc7c3525d4dbeee24bfa9bb3fe0d48ddc, 3f1d886cc7c3525d4dbeee24bfa9bb3fe0d48ddc, 3f1d886cc7c3525d4dbeee24bfa9bb3fe0d48ddc, 7c80229aa6e2707e59aa80cc041127cf9a79bcc9, 11fb04a111934eb8fbed077cd943719ed16c6447, 6.6.148, 5.15.217, 6.1.184unaffected
LinuxLinux6.10, 0, 6.6.151, 6.18.17, 6.19.7, 7.0affected
Weakness

CWE details

No CWE listed

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