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Linux Kernel CVE-2026-63846

| EUVDEUVD-2026-45530 HIGH
Improper Input Validation (CWE-20)
2026-07-19 Linux GHSA-85mj-cvf7-w5v9
Information Disclosure Linux
7.8
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
    Obtain local low-priv account with GPU access
  2. Delivery
    Open amdgpu DRI/render node
  3. Exploit
    Submit JPEG-ring CS with 64-bit user fence
  4. Execution
    Trigger unvalidated fence handling in JPEG v3.0 ring
  5. Persist
    Corrupt kernel/GPU memory or crash driver
  6. Impact
    Escalate privileges or deny service

Vulnerability Assessment

Weakness
CWE
CWE-20
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions

Requires local access to the machine and an authenticated low-privileged account able to open the AMD GPU DRI/render device and submit command streams (CVSS PR:L, AV:L, UI:N). The specific technical prerequisite is that the target runs the amdgpu driver on AMD hardware exposing a JPEG v3.0 ring, and the attacker submits a CS request carrying a 64-bit user fence to that JPEG ring - the exact condition the patch now rejects. Limiting factors: it is not remotely reachable, needs valid local credentials with GPU device permissions, and only affects systems with the relevant AMD GPU/JPEG v3.0 hardware and an unpatched kernel; systems without amdgpu or without that ring are not exposed.
Impact

The supplied CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, base 7.8) describes a local, low-privileged, low-complexity flaw with high confidentiality, integrity and availability impact - consistent with a driver bug reachable by any user holding a GPU render/DRI handle. Corroborating signals lower the urgency: EPSS is 0.17% (7th percentile), there is no CISA KEV listing, and no POC is referenced, so this is a real-but-not-urgent hardening fix rather than an actively exploited threat. Note a tension in the data: the vendor tag says 'Information Disclosure,' but the CVSS I:H/A:H and the nature of an unvalidated fence write imply memory corruption / DoS potential beyond mere disclosure - the exact exploit primitive is not detailed in the terse commit message and should be treated as inferred, not confirmed. Overall priority: routine patch on the normal kernel-update cadence; elevate only for multi-tenant hosts where untrusted local users share AMD GPUs.
Exploit ScenarioDerived

A local user with access to the AMD GPU render node crafts a JPEG-engine command submission that specifies a 64-bit user fence the JPEG v3.0 ring cannot correctly service, exercising the unvalidated write/handling path in an unpatched kernel. Depending on the resulting primitive this could corrupt kernel/GPU memory state or crash the driver (DoS), potentially aiding privilege escalation. No public POC is referenced, and exploitation requires prior local access.
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 20, 2026

Local privilege escalation / memory-corruption risk in the Linux kernel's AMD GPU (amdgpu) JPEG v3.0 ring driver, where the ring was allowed to accept command-stream submissions containing 64-bit user fences that the JPEG hardware cannot actually write. The fix flags the JPEG v3.0 ring as no_user_fence and rejects such CS submissions, closing an unvalidated-write condition reachable by any local user with GPU device access. No public exploit identified at time of analysis; EPSS is low (0.17%) and this is not on CISA KEV.

RemediationAI

Patch available per vendor advisory - upgrade to a fixed stable kernel for your branch (6.6.141, 6.12.91, 6.18.33, 7.0.10, or 7.1 or later per the ENISA EUVD data), or apply your distribution's backport of the commit that sets no_user_fence for the JPEG v3.0 ring (git.kernel.org/stable/c/ee035a9d3eed3a9f5a3e83c31a10b321c9598861 and the sibling stable commits). If you cannot patch immediately, the concrete compensating control is to restrict local access to the AMD GPU DRI/render devices - tighten permissions/ownership on /dev/dri/renderD* and /dev/dri/card* so only trusted users and services can submit GPU command streams; the trade-off is that GPU-accelerated workloads, containers, or compositors for restricted users will lose hardware acceleration. On multi-tenant or untrusted-user hosts, avoid exposing AMD GPU passthrough/JPEG engine access until patched. Cite and follow your distro's advisory for the exact backported package version rather than building from the raw commit.

Affected VersionsENISA

Linux patch: 6.12.91
Linux 5.9
Linux patch: 6.18.33
Linux patch: 0
Linux dfd57dbf44ddc70c90c76f83b2deb46e5dd40ce3 <303da8279f195cc741adc52c1b44d6b64de63bb0
Linux patch: 7.0.10
Linux patch: 7.1
Linux dfd57dbf44ddc70c90c76f83b2deb46e5dd40ce3 <5ada37d7f736f9feeaa06a25e470a4c74e67a61a
Linux dfd57dbf44ddc70c90c76f83b2deb46e5dd40ce3 <a2baf12eec41f246689e6a3f8619af1200031576
Linux dfd57dbf44ddc70c90c76f83b2deb46e5dd40ce3 <ee035a9d3eed3a9f5a3e83c31a10b321c9598861
Linux patch: 6.6.141
Linux dfd57dbf44ddc70c90c76f83b2deb46e5dd40ce3 <48ce00787e3fddd2b45692fc991b8ab128343da5

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 subsystem is amdgpu, the mainline Linux kernel driver for AMD Radeon/Instinct GPUs, specifically its JPEG (JPEG decode/encode engine) v3.0 ring. GPU command submission (CS) lets userspace hand command buffers to hardware rings; a 'user fence' is a memory location the GPU writes on completion so userspace can poll for progress. JPEG rings do not implement 64-bit user-fence writes, yet the driver did not mark the ring with no_user_fence, so it accepted CS requests specifying user fences the engine could not correctly service. The upstream commit (cherry-picked from 4d7d774f) sets no_user_fence for the JPEG v3.0 ring and rejects fenced submissions. No CWE was assigned by NVD; the root cause is best characterized as improper validation of a hardware-capability constraint on a memory-write primitive (missing input/capability validation, CWE-20 class), which the vendor tags loosely as 'Information Disclosure.'

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Severity by source

Vendor (Linux) PRIMARY 7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 7.8 HIGH

Local user with GPU render-node access (AV:L, PR:L) submits a malformed fenced CS with no user interaction; unvalidated kernel-memory handling yields high C/I/A.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

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

Lifecycle Timeline

4
CVSS changed
Jul 20, 2026 - 15:22 NVD
7.8 (HIGH)
Patch available
Jul 19, 2026 - 16:19 EUVD
CVE Published
Jul 19, 2026 - 14:04 cve.org
HIGH 7.8
CVE Published
Jul 19, 2026 - 14:04 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

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

drm/amdgpu/jpeg: set no_user_fence for JPEG v3.0 ring

JPEG rings do not support 64-bit user fence writes, reject CS submissions with user fences.

(cherry picked from commit 4d7d774f100efb5089c86a1fb8c5bf47c63fc9ef)

Executive ViewAI

Why It Matters

AMD GPU drivers in Linux systems contain a local privilege escalation vulnerability where users with GPU device access can corrupt system memory. No public exploit has been identified and assessed exploitation probability remains low (EPSS 0.17%). Organizations operating GPU-enabled infrastructure should prioritize patching, especially where GPU resources are shared across multiple users or workloads.

Business Impact: Medium
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.2%
Top 93% exploitable
Prevalence
High
amdgpu ships in mainline Linux, but only AMD-GPU hosts with JPEG v3.0 are exposed
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vendor VulDB

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
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
Medium

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

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Same weakness CWE-20 – Improper Input Validation

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CVE-2024-3400 CRITICAL POC
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CVE-2022-47966 CRITICAL POC
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CVE-2023-22515 CRITICAL POC
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CVE-2009-0927 HIGH POC
8.8
CVE-2017-9791 CRITICAL POC
9.8
CVE-2017-15944 CRITICAL POC
9.8
CVE-2019-0604 CRITICAL POC
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Same technique Information Disclosure

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CVE-2019-2725 CRITICAL POC
9.8
CVE-2021-34523 CRITICAL POC
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CVE-2013-2251 CRITICAL POC
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CVE-2017-5638 CRITICAL POC
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CVE-2025-24813 CRITICAL POC
9.8
CVE-2025-68613 HIGH POC
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CVE-2015-1701 HIGH POC
7.8
CVE-2017-0147 HIGH POC
7.5

Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise Module for Basesystem 15 SP7 Affected
SUSE Linux Enterprise Server 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP7 Affected

References

Advisories & patches
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-63846 ADVISORY https://seclists.org/oss-sec/2026/q3/230 ADVISORY https://ubuntu.com/security/notices/USN-8574-1 ADVISORY https://vuldb.com/vuln/380164 REF https://git.kernel.org/stable/c/303da8279f195cc741adc52c1b44d6b64de63bb0 REF https://git.kernel.org/stable/c/34d72bb699305992d3190220e331a95bfd3e9f7f REF https://git.kernel.org/stable/c/48ce00787e3fddd2b45692fc991b8ab128343da5 REF https://git.kernel.org/stable/c/5ada37d7f736f9feeaa06a25e470a4c74e67a61a REF https://git.kernel.org/stable/c/a2baf12eec41f246689e6a3f8619af1200031576 REF https://git.kernel.org/stable/c/ee035a9d3eed3a9f5a3e83c31a10b321c9598861

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