High

CVE-2026-68338 — net/packet: avoid fanout hook re-registration after unregister

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.

Published Aug 10, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Linux

CVSS base

7.8

High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < acb40ebfa5c4d62f84339fcbf713f2a9fd033a71≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < c820f4b7f2fa38f8769db0d0cefdd94e2721504d≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < 4628efbdc7affd094181f5263e65c1062e31f15f≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < 80ec024d53a05c60ad1d08968dcf745f10c1665c≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < 0a052e0808e015e68144a9877e6ef42b952c49fa≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < 1bc55c29cd85818e9052f17deb287d5a11fb817f≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < a885387dae7986a55bae5c77a15bdd447f64e9b9≥ dc99f600698dcac69b8f56dda9a8a00d645c5ffc and < 50aff80475abd3533eef4320477037e6fcc6b56e and 1 more version 3.1	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.8	CVSS 3.1	High	1.8	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
7.8	CVSS 3.1	High	—	—	Linux via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.

endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 15, 2026
CVSS changed · 7.8
Oct 15, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Aug 10, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

git.kernel.org/stable/c/1bc55c29cd85818e9052f17deb287d5a11fb817f
NIST National Vulnerability Database
git.kernel.org/stable/c/c820f4b7f2fa38f8769db0d0cefdd94e2721504d
NIST National Vulnerability Database
git.kernel.org/stable/c/acb40ebfa5c4d62f84339fcbf713f2a9fd033a71
NIST National Vulnerability Database
git.kernel.org/stable/c/80ec024d53a05c60ad1d08968dcf745f10c1665c
NIST National Vulnerability Database
git.kernel.org/stable/c/0a052e0808e015e68144a9877e6ef42b952c49fa
NIST National Vulnerability Database
git.kernel.org/stable/c/4628efbdc7affd094181f5263e65c1062e31f15f
NIST National Vulnerability Database
git.kernel.org/stable/c/a885387dae7986a55bae5c77a15bdd447f64e9b9
NIST National Vulnerability Database
git.kernel.org/stable/c/50aff80475abd3533eef4320477037e6fcc6b56e
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 15h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 15h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-68338 is "net/packet: avoid fanout hook re-registration after unregister", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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