CVE-2026-98318

Received Received - Intake

BaseFortify

Publication date: 2026-10-06

Last updated on: 2026-10-19

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate absolute native symlink targets before NT fixups With symlinkroot unset, an absolute target is copied without conversion to an NT drive path. Later code still assumes an NT prefix is present when modifying the target and calculating the print name length. For "/ab", this causes two failures: sym[5] and path[5] are written past their allocations, and plen -= 2 * poff subtracts an assumed 8-byte prefix from a 6-byte UTF-16 target, wrapping u16 plen to 65534. That underflow causes another overflow: memcpy() copies 65534 bytes into a 24-byte buffer. A user with write access to a mounted share can trigger these bugs with default settings. Validate the NT drive prefix, including an ASCII drive letter, before accessing fixed offsets or subtracting the prefix length.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-06

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-06

EPSS Evaluated

2026-10-18

NVD

CVE-2026-98318

EUVD

EUVD-2026-93303

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	3363da82e02f1bddc54faa92ea430c6532e2cd2e
Linux	Linux	3363da82e02f1bddc54faa92ea430c6532e2cd2e
Linux	Linux	b6ea7b6c6be65149ab6b8e37a9dd1671f76add1b
Linux	Linux	6.15.6
Linux	Linux	6.16

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a Linux kernel vulnerability in the SMB client where absolute symlink targets are not properly validated before NT path conversions. Without a symlink root set, an absolute target is copied without converting to an NT drive path. Later code assumes an NT prefix exists, leading to buffer overflows when modifying the target and calculating lengths. For example, with '/ab', memory writes exceed buffer limits and a length underflow causes a large memcpy into a small buffer. A user with write access to a mounted share can exploit this with default settings.

Detection Guidance

This vulnerability affects the Linux kernel's SMB client handling of symlink targets. Detection requires checking kernel versions and SMB client configurations. Use uname -a to verify kernel version and inspect SMB client logs for symlink-related errors. No direct commands detect this flaw without kernel inspection.

Impact Analysis

If you use a Linux system with SMB client functionality and have write access to a mounted share, an attacker could trigger memory corruption by creating a malicious symlink. This could lead to crashes, data corruption, or potentially arbitrary code execution on your system. The impact depends on system configuration and privileges.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a low-level Linux kernel issue involving memory corruption in SMB client symlink handling, which could lead to denial of service or potential code execution. Compliance impacts would only occur if exploitation disrupted systems handling sensitive data.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the smb client symlink handling vulnerability. Avoid mounting SMB shares with write access for untrusted users until the patch is applied.

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