CVE-2026-80668netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
- 9.8CriticalCVSS base score
- 0.60%Exploitation in 30 daysEPSS · top 51% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
- 2 days later
· 2 days later
Published
- 2 months later
· 2 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.60% · top 51% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected 9e1196d27ef496f404c76f7a9d03761142d991c4 – < 61ca26e1a45965590f7e477c4d6f711162642e1c
- affected 5e1c1d22268ae710c238342c8030c21daf298168 – < 3d7b808ec35291ee75dcdb2b6fe5f587bfe9b1df
- affected d52fa1fa7440676b8c238037a050ab008c22737f – < 02f7809a19fc88cfd9bc113a4bfe7add6305db39
- affected f338ced0473849c9f6ed0b77ca99f1aab5826787 – < bc6b1da681abe631ed21b7fdced48546189d64a4
- affected bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5 – < 7ec786f4230c2a9b2eaf97a2d45368933b49d2b2
- affected bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5 – < b8b09dc2bf35a00d4e0556b5d6308c7b917ebda2
- affected 497f99b26fffdc5635706d1b4811f1ed8ee21a5b
- affected 6.1.176 – < 6.1.191
- affected 6.6.143 – < 6.6.160
- affected 6.12.94 – < 6.12.114
- affected 6.18.24 – < 6.18.61
- affected 6.19.14 – < 6.20
- affected 7.0
- unaffected < 7.0
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.61 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/61ca26e1a45965590f7e477c4d6f711162642e1c (opens in a new tab)
- https://git.kernel.org/stable/c/3d7b808ec35291ee75dcdb2b6fe5f587bfe9b1df (opens in a new tab)
- https://git.kernel.org/stable/c/02f7809a19fc88cfd9bc113a4bfe7add6305db39 (opens in a new tab)
- https://git.kernel.org/stable/c/bc6b1da681abe631ed21b7fdced48546189d64a4 (opens in a new tab)
- https://git.kernel.org/stable/c/7ec786f4230c2a9b2eaf97a2d45368933b49d2b2 (opens in a new tab)
- https://git.kernel.org/stable/c/b8b09dc2bf35a00d4e0556b5d6308c7b917ebda2 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-67544 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-80668)Record last updated .