CVE-2026-98696
Description
A flaw was found in the Linux kernel's USB serial subsystem. A local user with administrative privileges could exploit this flaw to cause a Denial of Service (DoS) or memory corruption. During the unloading of a USB serial driver module, drivers are deregistered in an incorrect sequence, allowing completion handlers to access port data after it has been released, triggering a use-after-free condition.
Statement
An incorrect USB serial driver deregistration order can leave USB I/O active while serial port drivers are being unbound and their port data is released. A completion handler may then access freed port data, creating a race based use after free that can cause a kernel crash and may potentially affect confidentiality or integrity if the stale object access becomes controllable. For the CVSS the PR:H is selected because reliable triggering normally requires unloading or deregistering the kernel module through root or CAP_SYS_MODULE. AC:H reflects the timing window between an outstanding USB completion and port teardown. The issue is not network reachable. A connected USB device or a local process using the serial port may influence I/O timing, but neither normally controls module removal without additional privileges. Impact is at least a local denial of service via kernel crash and in the worst defensible case may include confidentiality or integrity impact due to the documented use after free.
Mitigation
Mitigation for this issue is either not available or the currently available options don't 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 | 4.1 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | High | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
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