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Linux Kernel CVE-2026-53234

| EUVDEUVD-2026-39325 HIGH
Use After Free (CWE-416)
2026-06-25 416baaa9-dc9f-4396-8d5f-8c081fb06d67 GHSA-86vm-vp8g-7929
Authentication Bypass Linux Use After Free Memory Corruption IBM Red Hat Suse
7.8
CVSS 3.1 · NVD
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Attack ChainAIDerived

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

  1. Access
    Gain local privileged access
  2. Delivery
    Trigger EMAC driver unbind/removal
  3. Exploit
    emac_remove frees hardware resources
  4. Execution
    Inbound packets invoke emac_irq/emac_poll
  5. Persist
    Access freed dev->emacp/dev->mal
  6. Impact
    Corrupt kernel memory (crash or escalate)

Vulnerability Assessment

Weakness
CWE
CWE-416
ASVS 5.0
V15 - Secure Coding and Architecture Memory lifecycle management
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

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Exploitation Conditions

Exploitation requires local access to a system running the IBM EMAC Ethernet driver (IBM/AMCC PowerPC 4xx-class hardware) and the ability to trigger driver unbind or device removal - an operation gated behind privileged (root) access to the driver's sysfs unbind interface. The use-after-free window is only reachable during the device-removal teardown sequence, and successful memory corruption further depends on winning a race: network packets must arrive and be processed in the interval between emac_remove() returning and the devres cleanup calling unregister_netdev(). Limiting factors: the vulnerability is not remotely reachable (AV:L), affects only the specific EMAC hardware/driver rather than generic Linux systems, and is timing-dependent, so it cannot be triggered against default idle configurations without deliberately inducing device removal under traffic.
Impact

Signals are mostly consistent and point to a genuine-but-low-priority local memory-corruption bug. The upstream CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, 7.8 HIGH) reflects local access with full CIA impact typical of a kernel UAF, but AC:L likely understates the difficulty: exploitation depends on winning a race between emac_remove() returning and devres cleanup, and on triggering device removal in the first place, which on Linux requires privileged (root) access to the driver unbind sysfs interface. EPSS is very low (0.18%, 7th percentile), there is no CISA KEV listing, and no public exploit identified at time of analysis - all consistent with a hardware-specific, hard-to-weaponize race. Note a data conflict: the input Tags include 'Authentication Bypass,' which is inconsistent with the description (a use-after-free during device removal) and appears to be a mislabeled tag; the actual weakness is memory corruption (CWE-416), not an auth bypass. Net assessment: patch as part of normal kernel hygiene, but this is not an emergency for most environments, especially those not running IBM PowerPC EMAC hardware.
Exploit ScenarioDerived

A local attacker with administrative access to a PowerPC system running the IBM EMAC driver initiates a driver unbind or device hot-removal while the EMAC interface is actively processing network traffic. Incoming packets during the narrow post-emac_remove() window drive emac_irq()/emac_poll() to dereference freed structures (dev->emacp, dev->mal), corrupting kernel memory to crash the host or, with careful heap grooming, attempt privilege escalation. No public exploit is identified at time of analysis, and the local vector plus timing-dependent race make reliable exploitation difficult.
This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 08, 2026

Use-after-free in the Linux kernel's IBM EMAC Ethernet driver (drivers/net/ethernet/ibm/emac) lets in-flight packet processing touch hardware resources that have already been freed during device removal, because devm_register_netdev() deferred unregister_netdev() until after emac_remove() tore down the hardware. A local attacker who can trigger driver unbind/hot-removal while the interface handles traffic can corrupt kernel memory, potentially escalating to code execution or crashing the system. This is a fixed regression window on IBM PowerPC EMAC hardware; no public exploit identified at time of analysis and EPSS risk is low (0.18%, 7th percentile).

RemediationAI

Vendor-released patch: upgrade to Linux 6.12.94, 6.18.36, 7.0.13, or 7.1 (or later on each branch), which move unregister_netdev() to the start of emac_remove() before hardware teardown. Distribution users should apply their vendor's kernel update incorporating the stable commits at https://git.kernel.org/stable/c/a0130d682222ae21afc395aead7cd2d87e1a8358 and the related commits listed in the NVD advisory (https://nvd.nist.gov/vuln/detail/CVE-2026-53234). If immediate patching is not possible, the practical compensating control is to avoid triggering the vulnerable path: do not perform driver unbind or hot-removal of EMAC interfaces (via /sys/bus/platform/drivers/.../unbind) on production systems, and restrict root/administrative access that would allow such removal, since the UAF window only opens during device teardown. There is no feature toggle that mitigates the underlying race, so patching is strongly preferred over the operational workaround.

Affected VersionsENISA

Linux patch: 6.18.36
Linux a4dd8535a527061a01f2fd335596fa77ca240a96 <cf8e14db93eaecc4c0c58299be3b3183b0e53ed5
Linux a4dd8535a527061a01f2fd335596fa77ca240a96 <c12584cd6078085d707266be864e7e1cc91d74e3
Linux a4dd8535a527061a01f2fd335596fa77ca240a96 <c09c2e236eef6f59e105f38a30f5439e6ccbcad7
Linux patch: 7.0.13
Linux 6.12
Linux patch: 0
Linux patch: 7.1
Linux a4dd8535a527061a01f2fd335596fa77ca240a96 <a0130d682222ae21afc395aead7cd2d87e1a8358
Linux patch: 6.12.94

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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Technical ContextAI · show details

The affected component is the IBM EMAC driver, which serves the Ethernet MAC controllers found on IBM/AMCC PowerPC 4xx and related embedded SoCs. The root cause is CWE-416 (Use-After-Free) arising from managed-device (devres) lifecycle ordering: devm_register_netdev() schedules unregister_netdev() to run in the devres cleanup phase, which executes AFTER emac_remove() returns. emac_remove() cancels work, detaches PHY/MAL modules, and unregisters from the Memory Access Layer (MAL), freeing resources such as dev->emacp and dev->mal. Between emac_remove() returning and devres cleanup completing, the netdev is still registered, so the network stack can invoke emac_irq(), emac_poll(), or other handlers that dereference the now-freed structures. The fix replaces devm_register_netdev() with a manual register_netdev() and moves unregister_netdev() to the very start of emac_remove(), guaranteeing the device is quiesced before any teardown. CPE data confirms the affected product is cpe:2.3:o:linux:linux_kernel across multiple 7.1 release candidates and stable branches.

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Severity by source

NVD PRIMARY 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 6.4 MEDIUM

Local UAF reachable only by triggering privileged device unbind (PR:H) and winning a teardown race (AC:H); kernel memory corruption yields full C/I/A impact.

3.1 AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:H/AT:N/PR:H/UI:N/VC:H/VI:H/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

Primary rating from NVD.

CVSS VectorNVD

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

Lifecycle Timeline

3
CVSS changed
Jul 08, 2026 - 19:07 NVD
7.8 (HIGH)
CVE Published
Jun 25, 2026 - 09:16 nvd
HIGH 7.8
CVE Published
Jun 25, 2026 - 09:16 cve.org
UNKNOWN (no severity yet)

DescriptionNVD

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

net: ibm: emac: Fix use-after-free during device removal

The driver was using devm_register_netdev() which causes unregister_netdev() to be deferred until the devres cleanup phase, which runs after emac_remove() returns. This creates a use-after-free window where:

  1. emac_remove() is called, which tears down hardware (cancels work, detaches

modules, unregisters from MAL)

  1. emac_remove() returns
  2. devres cleanup runs and finally calls unregister_netdev()

During step 3, the network stack might still process packets, triggering emac_irq(), emac_poll(), or other handlers that access now-freed hardware resources (dev->emacp, dev->mal, etc.).

Fix this by replacing devm_register_netdev() with manual register_netdev() and calling unregister_netdev() at the beginning of emac_remove(), before any hardware teardown. This ensures the network device is fully stopped and unregistered before hardware resources are released.

The change is safe because:

  • dev->ndev is assigned very early in probe (before any error paths that

could bypass emac_remove)

  • platform_set_drvdata() is only called after successful registration, so

emac_remove() only runs for fully registered devices

  • unregister_netdev() is idempotent and safe to call on any registered device

Executive ViewAI

Why It Matters

CVE-2026-53234 is a use-after-free vulnerability in the Linux kernel IBM EMAC Ethernet driver affecting PowerPC systems, enabling local privilege escalation with code execution potential. Although currently unpatched and lacking a public exploit (EPSS: 0.2%), the HIGH CVSS severity (7.8) and kernel memory corruption risk require immediate attention. Organizations with IBM PowerPC Linux infrastructure should prioritize mitigation and vendor patch readiness.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: (1) Restrict unprivileged access to device driver unbind operations through OS-level access controls and user privilege boundaries; (2) Disable EMAC driver on systems where it is not operationally required; (3) Monitor system logs for kernel use-after-free errors and unexpected terminations; (4) Implement network segmentation to minimize local access vectors to affected systems; (5) Establish expedited patching protocol for immediate kernel upgrade upon vendor advisory release.

Threat Intelligence Overview

EPSS Score
0.2%
Top 93% exploitable
Prevalence
Low
IBM PowerPC EMAC driver - niche embedded hardware, minimal enterprise footprint
Data Quality
4 sources
Confidence: Medium
EUVD NVD CVE.org EPSS Vendor

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 0.2%
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

39
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +39
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Use After Free HIGH

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory Corruption HIGH

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Same weakness CWE-416 – Use After Free

View all
CVE-2019-0708 CRITICAL POC
9.8
CVE-2015-5119 CRITICAL POC
9.8
CVE-2014-0322 HIGH POC
8.8
CVE-2012-4792 HIGH POC
8.8
CVE-2009-4324 HIGH POC
7.8
CVE-2015-0313 CRITICAL POC
9.8
CVE-2015-5122 CRITICAL POC
9.8
CVE-2013-2551 HIGH POC
8.8

Same technique Authentication Bypass

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CVE-2015-3306 CRITICAL POC
10.0
CVE-2023-22515 CRITICAL POC
9.8
CVE-2012-4681 CRITICAL POC
9.8
CVE-2013-2465 CRITICAL POC
9.8
CVE-2011-3544 CRITICAL POC
9.8
CVE-2022-40684 CRITICAL POC
9.8
CVE-2025-61882 CRITICAL POC
9.8
CVE-2024-0012 CRITICAL POC
9.3

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 16.0 Not-Affected

References

Advisories & patches
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-53234 ADVISORY https://ubuntu.com/security/notices/USN-8726-1 ADVISORY https://ubuntu.com/security/notices/USN-8727-1 REF https://git.kernel.org/stable/c/a0130d682222ae21afc395aead7cd2d87e1a8358 REF https://git.kernel.org/stable/c/c09c2e236eef6f59e105f38a30f5439e6ccbcad7 REF https://git.kernel.org/stable/c/c12584cd6078085d707266be864e7e1cc91d74e3 REF https://git.kernel.org/stable/c/cf8e14db93eaecc4c0c58299be3b3183b0e53ed5

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