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Linux Kernel EUVDEUVD-2026-64350

| CVE-2026-74663 HIGH
2026-08-22 Linux GHSA-qwcm-6g6c-27vm
7.8
CVSS 3.1 · Vendor: Linux
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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
5.5 MEDIUM

Stack exhaustion reliably causes kernel panic (A:H); confidentiality and integrity impact require exploiting the overflow past STACKPROTECTOR, which is not confirmed.

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

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 25, 2026 - 07:04 vuln.today
CVSS changed
Aug 25, 2026 - 06:22 NVD
7.8 (HIGH)
Patch available
Aug 22, 2026 - 16:01 EUVD
CVE Published
Aug 22, 2026 - 15:32 cve.org
HIGH 7.8
CVE Published
Aug 22, 2026 - 15:32 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

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

net/sched: reject overly deep qdisc hierarchies

Deep qdisc hierarchies can lead to excessive recursion in qdisc tree walkers and exhaust the kernel stack. The existing loop check does not cover the create-and-graft path, so a hierarchy can still be extended by creating a new child qdisc below an already deep parent.

Store the hierarchy depth in struct Qdisc and update it when qdiscs are grafted. Reject new child qdiscs once the parent is already at the maximum allowed depth.

AnalysisAI

Stack exhaustion in Linux kernel net/sched allows a local low-privileged attacker with CAP_NET_ADMIN to crash or potentially compromise the kernel by constructing an excessively deep qdisc hierarchy. The create-and-graft code path lacked depth enforcement, permitting hierarchies that trigger unbounded recursion in qdisc tree walkers, overflowing the kernel stack. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Gain local shell access
Delivery
Acquire CAP_NET_ADMIN via user namespace or privilege
Exploit
Iteratively graft child qdiscs past depth limit
Execution
Trigger recursive tree walker traversal
Persist
Exhaust kernel stack
Impact
Kernel panic or memory corruption

Vulnerability AssessmentAI

Exploitation Exploitation requires local system access and the CAP_NET_ADMIN capability in the relevant network namespace. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 7.8 vector (AV:L/AC:L/PR:L/UI:N) reflects realistic exploitation parameters - local access with low privilege - and the C:H/I:H/A:H triple-high impact suggests the vendor or NVD believes this is a privilege escalation vector, not just a crash. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A local attacker with access to a shell on the target system - or an attacker who has gained code execution in a container using rootless/user-namespace mode - uses 'tc qdisc add' in a tight loop to iteratively graft child qdiscs, building a hierarchy far deeper than the kernel's stack can safely recurse. When the kernel subsequently traverses the hierarchy (e.g., during a 'tc qdisc show' or qdisc deletion), recursion depth causes a kernel stack overflow, resulting in at minimum a kernel panic and potentially exploitable memory corruption. …
Remediation Upgrade to a patched Linux kernel version: 6.1.183 or later for the 6.1 stable branch, 6.6.152 or later for 6.6, 6.12.104 or later for 6.12, 6.18.45 or later for 6.18, 7.1.9 or later for 7.1, or 7.2 for the mainline branch. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, identify all Linux systems running vulnerable kernel versions and determine which have processes or users with CAP_NET_ADMIN capabilities. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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EUVD-2026-64350 vulnerability details – vuln.today

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