net/packet: avoid fanout hook re-registration after unregister
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 11 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: net/packet: avoid fanout hook re-registration after unregister packet_set_ring() temporarily detaches a socket from packet delivery while reconfiguring its ring. It records the previous running state, clears po->num, unregisters the protocol hook when needed, drops po->bind_lock, and later restores po->num and re-registers the hook from the saved was_running value. That unlocked window can race with NETDEV_UNREGISTER. The notifier can observe the socket as not running, skip __unregister_prot_hook(), and invalidate the per-socket binding by setting po->ifindex to -1 and clearing po->prot_hook.dev. A one-member fanout group can still retain its shared fanout hook device pointer. When packet_set_ring() resumes, re-registering solely from the stale was_running state can re-add the fanout hook after the device has been unregistered. Treat po->ifindex == -1 as an invalidated binding after reacquiring po->bind_lock. This is distinct from ifindex 0, the normal unbound/wildcard state: ifindex -1 marks an existing device binding that was invalidated when the device was unregistered. Restore po->num as before, but do not re-register the hook if device unregister already detached the socket.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6, 7.2
Red Hat 3 advisories
- RHSA-2026:91565 Released 2026-10-28 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- 10Base-SMTV kernel-modules-internal-6.12.0-211.69.1.el10_2
- Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.69.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.69.1.el10_2, kernel-64k-devel-6.12.0-211.69.1.el10_2 +12
- Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.69.1.el10_2, kernel-64k-6.12.0-211.69.1.el10_2, kernel-64k-core-6.12.0-211.69.1.el10_2 +29
- Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.69.1.el10_2, libperf-6.12.0-211.69.1.el10_2
- Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.69.1.el10_2
- Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.69.1.el10_2, kernel-rt-64k-6.12.0-211.69.1.el10_2, kernel-rt-64k-core-6.12.0-211.69.1.el10_2 +21
- Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.69.1.el10_2, kernel-rt-core-6.12.0-211.69.1.el10_2, kernel-rt-debug-6.12.0-211.69.1.el10_2 +9
- RHSA-2026:89083 Released 2026-10-24 · Red Hat rating Importantkernel security, bug fix, and enhancement update
- Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.178.1.el8_10, kernel-4.18.0-553.178.1.el8_10, kernel-abi-stablelists-4.18.0-553.178.1.el8_10 +19
- Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.178.1.el8_10
- RHSA-2026:89082 Released 2026-10-24 · Red Hat rating Importantkernel-rt security, bug fix, and enhancement update
- Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-core-4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-4.18.0-553.178.1.rt7.519.el8_10 +9
- Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-core-4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-4.18.0-553.178.1.rt7.519.el8_10 +7
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 7 | Affected | No fix yet |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| 10Base-SMTV | Fixed | RHSA-2026:91565 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:91565 |
| Red Hat Enterprise Linux BaseOS (v. 10) | Fixed | RHSA-2026:91565 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2026:89083 |
| Red Hat Enterprise Linux CRB (v. 8) | Fixed | RHSA-2026:89083 |
| Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) | Fixed | RHSA-2026:91565 |
| Red Hat Enterprise Linux Hidden (v. 10) | Fixed | RHSA-2026:91565 |
| Red Hat Enterprise Linux NFV (v. 8) | Fixed | RHSA-2026:89082 |
| Red Hat Enterprise Linux RT (v. 8) | Fixed | RHSA-2026:89082 |
| Red Hat Enterprise Linux Real Time (v. 10) | Fixed | RHSA-2026:91565 |
| Red Hat Enterprise Linux Real Time for NFV (v. 10) | Fixed | RHSA-2026:91565 |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-68338
- 2026-10-03 Alias added: GHSA-xrw5-g7cv-c5p3
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-20 Weakness changed · CISA ADP
- 2026-10-26 Fix available: RHSA-2026:89083 · Red Hat
- 2026-10-26 Fix available: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · Red Hat
- 2026-10-26 Fix available: RHSA-2026:89082 · Red Hat
- 2026-10-26 Fix available: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · Red Hat
- 2026-10-29 Fix available: RHSA-2026:91565 · Red Hat
- 2026-10-29 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) +4 · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/acb40ebfa5c4d62f84339fcbf713f2a9fd033a71
- https://git.kernel.org/stable/c/c820f4b7f2fa38f8769db0d0cefdd94e2721504d
- https://git.kernel.org/stable/c/4628efbdc7affd094181f5263e65c1062e31f15f
- https://git.kernel.org/stable/c/80ec024d53a05c60ad1d08968dcf745f10c1665c
- https://git.kernel.org/stable/c/0a052e0808e015e68144a9877e6ef42b952c49fa
- https://git.kernel.org/stable/c/1bc55c29cd85818e9052f17deb287d5a11fb817f
- https://git.kernel.org/stable/c/a885387dae7986a55bae5c77a15bdd447f64e9b9
- https://git.kernel.org/stable/c/50aff80475abd3533eef4320477037e6fcc6b56e
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Sources
- CVE-2026-68338 · CVE Program
- CVE-2026-68338 · NVD
- FIRST EPSS
- GHSA-xrw5-g7cv-c5p3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-68338 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences