CVE-2026-98017
Description
A flaw was found in the Linux kernel's network traffic control subsystem. This flaw allows a local user with network administration privileges to cause a denial of service (DoS) or potentially escalate privileges. A use-after-free condition occurs when the kernel prematurely deallocates network queueing structures after a failed configuration request while concurrent packet processing routines are still referencing them.
Statement
A MODERATE severity use-after-free flaw was found in the Linux kernel's network traffic control (net/sched) subsystem, affecting the Red Hat Enterprise Linux kernel and kernel-rt packages. When an RTM_NEWQDISC netlink request binds a populated shared ingress block via clsact and then fails estimator setup because of an invalid TCA_RATE parameter, the error-unwind path synchronously frees the containing queueing discipline (qdisc) while lockless readers in tc_run() may still hold references to it. A local user with the privileges required to configure network traffic control (CAP_NET_ADMIN) could win this race to crash the kernel, resulting in a denial of service. Red Hat rates this flaw MODERATE (CVSS 5.5, AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) because exploitation requires local access with network administration privileges and the established impact is loss of availability; this differs from the upstream CVEORG score of 7.8, which assumes high confidentiality and integrity impacts that Red Hat's assessment does not establish for this issue.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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