CVE-2026-80744
Received Received - Intake

Memory allocation warning suppression in Linux kernel nf_tables

Publication date: 2026-09-03

Last updated on: 2026-09-03

Assigner: kernel.org

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.

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Meta Information

Published
2026-09-03
Last Modified
2026-09-03
Generated
2026-09-03
AI Q&A
2026-09-03
EPSS Evaluated
N/A
NVD
CVE-2026-80744
EUVD
EUVD-2026-70348

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 5.10

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability involves a false positive warning in the Linux kernel's netfilter subsystem. When memory allocation fails during network flow offloading operations, the kernel incorrectly triggers a warning (WARN_ON_ONCE) even though memory allocation failures are expected under low-memory conditions. The issue occurs in nft_flow_rule_offload_abort() where errors like -ENOMEM are treated as kernel bugs when they are actually normal behavior.

Detection Guidance

This vulnerability triggers a kernel warning during nf_tables transaction processing under memory pressure. Check kernel logs for WARN_ON_ONCE messages related to nft_flow_rule_offload_abort or nft_flow_rule_offload_commit. Use commands like 'dmesg | grep -i nft_flow_rule_offload' or 'journalctl -k | grep -i nft_flow_rule_offload' to detect these warnings.

Impact Analysis

This vulnerability primarily causes unnecessary warning messages in system logs during memory pressure situations. It does not directly compromise security or functionality but may make debugging harder by flooding logs with false alarms. Users might see repeated warnings during normal operation when the system is low on memory.

Mitigation Strategies

Apply the kernel patch that changes the condition to WARN_ON_ONCE(err && err != -ENOMEM). Update to a fixed kernel version where this change is included. Monitor memory usage to prevent low-memory conditions that trigger the issue.

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