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Fencer Vulns
no cvss —

CVE-2026-98851 json

netfilter: nft_flow_offload: drop flowtable reference on init error path

published 2026-10-18 21 d ago modified 2026-10-30 9 d ago also EUVD-2026-103791

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.113, 6.18.56, 7.2.10, 7.3
  • linux Debian 13 6.12.113-1
  • linux Debian 14 7.2.10-1
  • linux-6.12 Debian 12 6.12.113-1~deb12u1

debian advisories DEBIAN-CVE-2026-98851

  • kernel Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-109341

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-2026-98851 updated cvss 3.3

kernel: netfilter: nft_flow_offload: drop flowtable reference on init error path

  • 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 Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    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
    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

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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