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Linux Kernel CVE-2026-97608

| EUVDEUVD-2026-86739 HIGH
2026-09-25 Linux GHSA-gqgj-ww6j-qxj3
7.0
CVSS 3.1 · Vendor: Linux
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Gain local CAP_NET_ADMIN in netns
  2. Delivery
    Trigger nf_log backend teardown
  3. Exploit
    Race sysctl/netlink rebind of logger
  4. Execution
    Free of backend module memory
  5. Persist
    Stale per-net pointer dereferenced
  6. Impact
    Use-after-free kernel crash (DoS)

Vulnerability Assessment

Exploitation Conditions

Requires local access with the ability to drive netfilter logger (re)binding - realistically CAP_NET_ADMIN in the target network namespace to write the net.netfilter.nf_log sysctl or issue nfnetlink logging configuration. The affected code paths are the nf_log_syslog and nfnetlink_log backends, and exploitation depends on winning a timing race between unregister_pernet_subsys() per-net teardown (module unload or namespace exit) and a concurrent writer that rebinds the still-registered global logger. Limiting factors: local-only vector, no remote reach, high attack complexity (narrow race window), and dependence on the backend being torn down while a rebind is in flight - this is not exploitable against a steady-state running system without inducing the teardown/rebind race.

Impact

This is a classic 'high-CVSS-but-modest-real-risk' Linux kernel race. The NVD CVSS of 7.0 (AV:L/AC:H/PR:L/UI:N/C:H/I:H/A:H) is internally reasonable on vector but the C:H/I:H impact ratings are overstated for what the description actually describes: a use-after-free triggered by an unregister-ordering race in the netfilter nf_log backends (nf_log_syslog, nfnetlink_log). The realistic outcome is a stale per-net logger pointer dereference into freed module memory - a memory-corruption/crash (DoS) primitive, not a demonstrated confidentiality or integrity compromise. All exploitation signals point to low urgency: no EPSS score provided, not in CISA KEV, and no public exploit identified. SSVC framing would be exploitation:none, automatable:no (a narrow timing race requiring local privilege), technical impact best characterized as partial/DoS rather than total. CONFLICT TO NOTE: the 'Information Disclosure' tag contradicts both the description (a write-side rebind race causing a dangling read, i.e., UAF/DoS) and CWE=N/A; treat the info-disclosure framing as unsupported. The AC:H rating is correct - winning the race requires precise timing between per-net teardown/module exit and a concurrent sysctl/netlink writer. Overall: patch in normal maintenance cadence, not an emergency.

Exploit ScenarioDerived

A local user with CAP_NET_ADMIN in a network namespace repeatedly writes to the net.netfilter.nf_log sysctl (or sends nfnetlink logging config) to rebind a logger at the exact moment nf_log_syslog/nfnetlink_log is being torn down (module unload or netns exit), re-binding the still-registered global backend after the per-net selection was cleared. Once the module frees its backend memory, a subsequent sysctl read or packet-logging path dereferences the now-stale per-net logger pointer, causing a use-after-free and kernel crash. No public exploit code is identified, and the narrow race window (AC:H) makes reliable exploitation difficult.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 25, 2026

Linux kernel netfilter logging (the nf_log_syslog and nfnetlink_log backends) contains a teardown-ordering race that leaves a stale per-network-namespace logger pointer which later sysctl reads or packet-logging operations dereference. A local actor able to rebind the kernel's log backend - realistically requiring CAP_NET_ADMIN in the target network namespace - must win a narrow timing window against module unload or network-namespace exit, so the assessed impact is no confidentiality loss, limited integrity impact, and high availability impact (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H). Vendor patches are available in stable releases 6.12.111, 6.18.53 and 7.2.7 (mainline 7.3-rc3), and no public exploit code or confirmed in-the-wild exploitation has been identified at time of analysis.

RemediationAI

Vendor-released patches are available: upgrade to Linux kernel stable 6.12.111, 6.18.53 or 7.2.7, or to mainline 7.3-rc3 or later, which contain the ordering fix (commit eaec35fae8f2052c1878a5c7cc7699d8357d79f2 and stable backports 2c018cc4842c33f0c732962e2ab58635e8ae5823, 64803ba0a05791cf9ca874466480e4c4cadaf7ab and dce24f3a146948595bb1b86347f31e20b4975daa); see https://nvd.nist.gov/vuln/detail/CVE-2026-97608 and the linked kernel.org commits. Because the bug requires a privileged local actor to rebind the logger while the backend is being torn down (typically during nf_log_syslog/nfnetlink_log module unload or network-namespace exit), practical compensations until patching are to avoid unloading those netfilter logging modules on running production hosts, and to deny untrusted users the CAP_NET_ADMIN context needed to race the rebind - for example kernel.unprivileged_userns_clone=0 on Debian/Ubuntu or user.max_user_namespaces=0, with the trade-off that rootless containers, sandboxes and some browser sandboxes that rely on unprivileged user namespaces stop working. Restricting write access to the net.netfilter.nf_log sysctls and to NETLINK_NETFILTER sockets to trusted administrators with CAP_NET_ADMIN narrows exposure with little operational cost. Since no public exploit code or confirmed active exploitation has been identified, environments where the teardown/rebind race is not attacker-reachable can patch on a normal maintenance cadence.

Affected VersionsENISA

Linux patch: 6.12.111
Linux 5b023fc8d8e0997e0b7ea6506d243afd5478c96e <2c018cc4842c33f0c732962e2ab58635e8ae5823
Linux patch: 7.3-rc3
Linux patch: 6.18.53
Linux 3.10
Linux 5b023fc8d8e0997e0b7ea6506d243afd5478c96e <dce24f3a146948595bb1b86347f31e20b4975daa
Linux 5b023fc8d8e0997e0b7ea6506d243afd5478c96e <64803ba0a05791cf9ca874466480e4c4cadaf7ab
Linux patch: 7.2.7
Linux 5b023fc8d8e0997e0b7ea6506d243afd5478c96e <eaec35fae8f2052c1878a5c7cc7699d8357d79f2
Linux patch: 0

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

nf_log is the Linux netfilter packet-logging framework: nf_log_syslog (the syslog backend) and nfnetlink_log (the NFLOG backend) each register a global logger in the kernel's loggers[pf][type] table and also maintain a per-network-namespace selection in net->nf.nf_loggers[pf], protected by nf_log_mutex and RCU. The flawed teardown sequence called unregister_pernet_subsys(), whose nf_log_unset() pre-exit callback clears the per-net pointer, before nf_log_unregister() removed the global backend entry. A concurrent writer (the net.netfilter.nf_log sysctl or an nfnetlink_log configuration message) could acquire nf_log_mutex in that window, rediscover the still-registered global logger, and re-install it into the per-net table; the module would then exit and free the backend memory, leaving a dangling per-net pointer that a later sysctl read or logging call dereferences. The upstream fix reverses the ordering - unregistering the global logger backends first - so writers can no longer rebind, while unregister_pernet_subsys() still waits for an RCU grace period after the pre-exit callback and nf_log_unregister() continues to cover readers of the global table. The record assigns no CWE, but the described flaw is a classic race-condition-to-use-after-free pattern reached only through local teardown paths (module unload or net namespace exit) concurrent with a privileged rebind; CPE data records cpe:2.3:a:linux:linux for the kernel.

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Severity by source

Vendor (Linux) PRIMARY 7.0 HIGH
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 5.3 MEDIUM

Local privileged writer (PR:L) must win a narrow teardown/rebind race (AC:H); outcome is a UAF crash (A:H) with limited memory corruption (I:L) and no real disclosure (C:N).

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
4.0 AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
SUSE 6.4 MEDIUM
AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Red Hat 7.0 MEDIUM

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

4
CVSS changed
Sep 25, 2026 - 15:22 NVD
7.0 (HIGH)
Patch available
Sep 25, 2026 - 11:02 EUVD
CVE Published
Sep 25, 2026 - 10:22 cve.org
HIGH 7.0
CVE Published
Sep 25, 2026 - 10:22 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_log: unregister loggers before per-net teardown

nf_log_syslog and nfnetlink_log unregister their per-network namespace operations before unregistering their global logger backends. This leaves a window where a sysctl or netlink writer can rebind the still- registered logger after the per-net pre-exit callback cleared the old selection.

The race looks like this:

CPU 0 CPU 1 ---- ---- unregister_pernet_subsys() nf_log_unset(net, logger) net->nf.nf_loggers[pf] = NULL

lock nf_log_mutex find logger in loggers[][] net->nf.nf_loggers[pf] = logger unlock nf_log_mutex

nf_log_unregister(logger) lock nf_log_mutex loggers[pf][type] = NULL unlock nf_log_mutex synchronize_rcu() module exit returns module core frees backend memory

Later, a sysctl read or packet logging operation can dereference the stale per-net logger pointer.

Fix this by unregistering the global logger backends before tearing down per-net state. Once the global registrations are gone, later writers can no longer rebind the logger. unregister_pernet_subsys() already waits for an RCU grace period after the pre-exit callback clears the per-net selection, while nf_log_unregister() continues to cover readers of the global logger table.

Apply this ordering fix to both nf_log backends that combine per-net teardown with global logger registration.

Executive ViewAI

Why It Matters

A race condition in the Linux kernel's netfilter logging subsystem can let an authenticated local user with CAP_NET_ADMIN privileges crash or destabilize affected systems, creating a denial-of-service risk for production servers, container hosts, and network appliances. While exploitation demands elevated local access and precise timing, the resulting availability loss could disrupt business-critical services and multi-tenant workloads. Leadership should treat this as a high-priority patching event to prevent unplanned downtime across the Linux estate.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.1%
Top 97% exploitable
Prevalence
Low
Linux kernel ubiquitous but netfilter nf_log backends as a loadable/teardown-raced path are niche
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
High

Priority Score

35
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +35
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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