CVE-2026-80668: netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- 0.7%
EPSS score, percentile 51.9 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 9.8 Critical
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- from 6.6.143 to before 6.6.160
- from 6.12.94 to before 6.12.114
- from 6.1.176 to before 6.2
- from 6.18.24 to before 6.19
- from 6.19.14 to before 6.20
- 7.0
Unaffected before 7.0; 6.6.160; 6.12.114; 7.1.5; 7.2
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | from 5e1c1d22268a to before 3d7b808ec352 |
| Affected | from d52fa1fa7440 to before 02f7809a19fc |
| Affected | from bffcaad9afdf to before 7ec786f4230c |
| Affected | from bffcaad9afdf to before b8b09dc2bf35 |
| Affected | 9e1196d27ef4 |
| Affected | f338ced04738 |
| Affected | 497f99b26fff |
| Affected | from 6.6.143 to before 6.6.160 |
| Affected | from 6.12.94 to before 6.12.114 |
| Affected | from 6.1.176 to before 6.2 |
| Affected | from 6.18.24 to before 6.19 |
| Affected | from 6.19.14 to before 6.20 |
Versions not listed are: unaffected.
| Status | Versions |
|---|---|
| Affected | 7.0 |
| Unaffected | before 7.0 |
| Unaffected | 6.6.160 |
| Unaffected | 6.12.114 |
| Unaffected | 7.1.5 |
| Unaffected | 7.2 |
Versions not listed are: affected.
Versions the record lists as unaffected: 6.6.160, 6.12.114, 7.1.5, 7.2.
Source: CVE List, as of . About the data.
About this vulnerability
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_expect: use conntrack GC to reap expectations This patch replaces the timer API by GC worker approach for expectations, as it already happened in many other subsystems. Use the existing conntrack GC worker to iterate over the local list of expectations in the master conntrack to reap expired expectation…
Summary: CVE record, as of .
- CISA has not added CVE-2026-80668 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 28 Aug 2026.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.7% (percentile 51.9), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_expect: use conntrack GC to reap expectations This patch replaces the timer API by GC worker approach for expectations, as it already happened in many other subsystems. Use the existing conntrack GC worker to iterate over the local list of expectations in the master conntrack to reap expired expectations. Check IPS_HELPER_BIT to run GC for expectations, set it on for nft_ct expectation which nevers sets it. Hold the expectation spinlock while iterating over the master conntrack expectation list to synchronize with nf_ct_remove_expectations(). This also performs runtime packet path garbage collection through the expectation insertion and lookup functions while walking over one of the chains of the global expectation hashtables. Unconfirmed conntrack entries are skipped since ct->ext can be reallocated and dying are skipped since those will be gone soon. Set on IPS_HELPER_BIT if the helper ct extension is added, then the new GC worker does not need to bump the ct refcount to check if the ct->ext helper is available. This removes the extra bump on the refcount for expectation timers, this allows to remove several nf_ct_expect_put() calls after the unlink, after this update only refcount remains at 1 while on the expectation hashes. This patch implicitly addresses a race with the existing timer API allowing an expectation to access a stale exp->master pointer which has been already released when expectation removal loses races with an expiring timer, ie. timer_del() reporting false. Add a new NF_CT_EXPECT_DEAD flag to reap this expectation via GC. This is needed by nf_conntrack_unexpect_related() which is called in error paths to invalidate newly created expectations that has been added into the hashes. These expectactions cannot be inmediately released as GC or nf_ct_remove_expectations() could race to make it. On expectation insert, the runtime GC reaps stale expectations before checking the expectation limit set by policy. Set current timestamp in nf_ct_expect_alloc(), then add the expectation policy timeout (or custom timeout specified added on top of this) to specify the expectation lifetime.
Source: CVE List, as of . About the data.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
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