# CVE-2026-80744: netfilter: nf_tables_offload: suppress WARN_ON_ONCE for ENOMEM in abort path

> A local attacker can trigger kernel warnings and potential instability in the netfilter offload abort path during memory pressure, requiring a kernel patch.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** AZL-99066, BELL-CVE-2026-80744, DEBIAN-CVE-2026-80744, GHSA-9x57-56r2-6794, UBUNTU-CVE-2026-80744

## What is CVE-2026-80744?

CVE-2026-80744 is a denial of service vulnerability in Linux, published on 3 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

netfilter: nf_tables_offload: suppress WARN_ON_ONCE for ENOMEM in abort path

In nft_flow_rule_offload_abort(), WARN_ON_ONCE(err) is triggered on every
error during rollback, including -ENOMEM. Memory allocation failures are
expected under low-memory conditions and do not indicate a kernel bug.

Trace for example:
nft_flow_offload_chain() // FLOW_BLOCK_BIND
  nft_flow_block_chain()
    nft_chain_offload_cmd()
      nft_block_offload_cmd()
        ->ndo_setup_tc()
        nsim_setup_tc()
          flow_block_cb_setup_simple()
            flow_block_cb_alloc() // fails to -ENOMEM

The warning was reproduced on the 5.10 stable kernel under memory pressure
via fault injection, but the underlying bug exists in mainline as well,
as demonstrated by the ENOMEM trace above. The following splat was
triggered during nf_tables transaction processing:

WARNING: CPU: 0 PID: 8567 at net/netfilter/nf_tables_offload.c:532 nft_flow_rule_offload_abort net/netfilter/nf_tables_offload.c:532 [inline]
WARNING: CPU: 0 PID: 8567 at net/netfilter/nf_tables_offload.c:532 nft_flow_rule_offload_commit+0x971/0xcd0 net/netfilter/nf_tables_offload.c:591
Modules linked in:
CPU: 0 PID: 8567 Comm: syz-executor.0 Not tainted 5.10.260-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:nft_flow_rule_offload_abort net/netfilter/nf_tables_offload.c:532 [inline]
RIP: 0010:nft_flow_rule_offload_commit+0x971/0xcd0 net/netfilter/nf_tables_offload.c:591
Call Trace:
 nf_tables_commit+0x3bd/0x4bd0 net/netfilter/nf_tables_api.c:8604
 nfnetlink_rcv_batch+0xb1e/0x1f20 net/netfilter/nfnetlink.c:509
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:579 [inline]
 nfnetlink_rcv+0x3b3/0x420 net/netfilter/nfnetlink.c:597
 netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
 netlink_unicast+0x6cd/0xa00 net/netfilter/af_netlink.c:1340
 netlink_sendmsg+0x906/0xe10 net/netfilter/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:651 [inline]
 __sock_sendmsg+0x155/0x190 net/socket.c:663
 ____sys_sendmsg+0x705/0x870 net/socket.c:2379
 ___sys_sendmsg+0x100/0x170 net/socket.c:2433
 __sys_sendmsg+0xe9/0x1c0 net/socket.c:2462
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x67/0xd1

Change the condition to WARN_ON_ONCE(err && err != -ENOMEM) so that
warnings are only emitted for unexpected errors. This aligns with the
common kernel practice of not warning on -ENOMEM.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

## Which versions are affected by CVE-2026-80744?


## How do I fix CVE-2026-80744?

Apply the vendor's patch.

## Is CVE-2026-80744 being exploited?

There is no known exploitation of CVE-2026-80744 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80744 and fix it if it is affected.

What it is: CVE-2026-80744 is a denial of service vulnerability in Linux, published on 3 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80744 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-80744/ (Markdown: https://insights.sbomify.com/CVE-2026-80744/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80744
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80744
- OSV: https://osv.dev/vulnerability/CVE-2026-80744

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80744/
Summaries are generated and may contain mistakes; the official description above is the record.