CVE-2026-93828
Description
A flaw was found in the Linux kernel's exFAT file system. A local user capable of mounting a corrupted or maliciously crafted storage volume can trigger an integer calculation error when the system processes an uppercase translation table with a size of zero. This failure causes the kernel to enter an infinite loop, leading to a Denial of Service (DoS) condition.
Statement
A low-impact flaw was found in the Linux kernel's exFAT file system implementation. When a damaged or maliciously crafted exFAT volume declares a size of zero for its uppercase (upcase) translation table in the on-disk directory entry, an integer calculation error in exfat_create_upcase_table() causes the kernel to enter an infinite loop while attempting to load the table, resulting in a denial of service (system hang). Exploitation requires local access with privileges sufficient to mount an attacker-supplied or corrupted storage volume, and only availability is affected; there is no impact on confidentiality or integrity.
Red Hat Enterprise Linux 6 and 7 (kernel and kernel-rt) and the RHEL 8.4, 8.6, 8.8, and 8.10 kernel and kernel-rt update streams are not affected because the vulnerable code is not present in those kernels. The RHEL 9 and RHEL 10 kernels and their kernel-rt variants, the Red Hat In-Vehicle OS kernel components, and OpenShift Container Platform 4 and 5 releases shipping Red Hat Enterprise Linux CoreOS 9 are affected. For these affected products the fix is deferred, so no kernel update carrying the fix is currently planned; the residual risk is a denial of service that can be triggered only by a privileged local user or process mounting a crafted exFAT volume. Red Hat rates this flaw as low impact based on this limited practical exploitability, even though the corresponding Red Hat CVSS:3.1 base score is 5.5 (Moderate) for the vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
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 | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | 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:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.
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