VulnerabilityPublished 4 Sep 2026Updated 3 Oct 2026

CVE-2026-80837: Linux kernel · netfilter: nf_tables: don't queue packet path object notifications

Affects Linux kernelSource GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 12:55 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-cj8h-w72f-5pwh

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-34.34 22 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1013.13 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1014.14 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1013.13 8 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1013.13 12 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1007.8 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented in the Linux kernel that changes the notification handling to avoid queuing notifications from the packet path without proper locking. Users should update to a kernel version that includes this fix. Since no vendor advisory or patch links are provided, check the Linux kernel mailing lists or official kernel releases for the patch and upgrade accordingly.

Description

A use-after-free vulnerability in the Linux kernel's netfilter nf_tables subsystem was resolved. The issue arises from queuing packet path object notifications without proper synchronization, leading to a race condition where a freed sk_buff structure is accessed. This occurs when notifications are enqueued without holding the commit_mutex, causing potential memory corruption. The fix restores immediate sending of notifications from the packet path and retains queuing only within netlink transactions under commit_mutex protection.

Impact

This vulnerability can cause kernel memory corruption due to a use-after-free condition in the nf_tables notification mechanism. While no direct exploit code or active exploitation is reported, the memory corruption could potentially lead to system instability or denial of service. No evidence of privilege escalation or remote code execution is provided in the data.

Summary

The vulnerability in the Linux kernel's netfilter nf_tables subsystem involves the nft_obj_notify() function, which is called from the packet path with GFP_ATOMIC allocation but without holding a mutex. Since commit 67cc570edaa0, notifications are queued onto a notify_list without locking, which is only protected by commit_mutex in other contexts. This leads to a race condition between list_add_tail() and list_del() + kfree_skb() on different CPUs, causing a use-after-free of an sk_buff. The bug manifests as a KASAN slab-use-after-free error. The fix splits message construction and changes nft_obj_notify() to send notifications immediately from the packet path, while queuing remains only in netlink transactions under commit_mutex, preventing the race.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 04:11 UTC

Technical details

References

Community reviews

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