CVE-2026-93785

Received Received - Intake

CIFS IDMAP Key Payload Length Validation Flaw

Publication date: 2026-09-24

Last updated on: 2026-10-03

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: cifs: validate idmap key payload length The cifs.idmap key type stores its payload length in key->datalen, which is limited to U16_MAX. Accepting a larger key payload truncates the recorded length and can make later users interpret the payload using inconsistent bounds. Reject oversized preparsed payloads before allocating or copying them. This keeps key->datalen consistent with the stored data for both inline and separately allocated idmap payloads.

CVSS Scores

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Meta Information

Published

2026-09-24

Last Modified

2026-10-03

Generated

2026-10-15

AI Q&A

2026-09-24

EPSS Evaluated

2026-10-13

NVD

CVE-2026-93785

EUVD

EUVD-2026-86172

Affected Vendors & Products

Vendor	Product	Version / Range
linux_kernel	cifs	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves the CIFS (Common Internet File System) idmap key type. The issue occurs when the payload length stored in key->datalen exceeds U16_MAX, causing truncation. This can lead to inconsistent data interpretation later, as the recorded length no longer matches the actual payload size.

Detection Guidance

This vulnerability affects the Linux kernel's CIFS (Common Internet File System) module, specifically the cifs.idmap key type. Detection requires checking for oversized preparsed payloads in the CIFS idmap key handling. No specific commands are provided in the context, but you can monitor kernel logs for CIFS-related errors or warnings using dmesg or journalctl.

Impact Analysis

If exploited, this flaw could allow an attacker to manipulate data interpretation in CIFS idmap operations, potentially leading to unauthorized access or data corruption. Systems using CIFS for file sharing may be affected.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a Linux kernel issue related to CIFS idmap key payload handling, which could lead to data corruption or misinterpretation but does not inherently violate regulatory requirements.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the cifs.idmap key payload length validation issue. Monitor vendor advisories for kernel updates addressing this CVE.

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