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CVE-2026-89631

Опубликовано: 11 сент. 2026
Источник: redhat
CVSS3: 5.7
EPSS Низкий

Описание

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject a tree connect response whose byte count is too small CIFSTCon() bounds its strnlen() over the byte area with the server's ByteCount minus two, which for ByteCount 0 or 1 goes negative as an int and converts to a huge size_t. The later subtraction wraps the __u16 bytes_left, and that is what bounds cifs_strndup_from_utf16(): a bound of up to 65535 against a ~16 KB cifs_req_poolp object runs off the end of the slab object, and the bytes reach userspace through tcon->nativeFileSystem in /proc/fs/cifs/DebugData. Reject a byte area too small for what the parser consumes. Two bytes is the least it can consume, and no conformant response carries fewer. The new trace point is the 129th smb_eio_trace entry, which __mode(byte) cannot represent, so the attribute goes with it.

A flaw was found in the Linux kernel's Server Message Block (SMB) client. A remote malicious SMB server could send a specially crafted tree connect response with a byte count that is too small. This incorrect handling can lead to an integer underflow, causing the client to read beyond an allocated memory buffer. Consequently, sensitive information from kernel memory may be exposed to a local user through the /proc/fs/cifs/DebugData interface.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat OpenShift Container Platform 4openshift/ose-rhel-coreos-8Fix deferred
Red Hat OpenShift Container Platform 4openshift/ose-rhel-coreos-9Fix deferred

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Дополнительная информация

Статус:

Moderate
Дефект:
CWE-125
https://bugzilla.redhat.com/show_bug.cgi?id=2532089kernel: Linux Kernel: Information disclosure in SMB client due to small byte count in tree connect response

EPSS

Процентиль: 38%
0.00448
Низкий

5.7 Medium

CVSS3

Связанные уязвимости

CVSS3: 9.1
ubuntu
6 дней назад

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject a tree connect response whose byte count is too small CIFSTCon() bounds its strnlen() over the byte area with the server's ByteCount minus two, which for ByteCount 0 or 1 goes negative as an int and converts to a huge size_t. The later subtraction wraps the __u16 bytes_left, and that is what bounds cifs_strndup_from_utf16(): a bound of up to 65535 against a ~16 KB cifs_req_poolp object runs off the end of the slab object, and the bytes reach userspace through tcon->nativeFileSystem in /proc/fs/cifs/DebugData. Reject a byte area too small for what the parser consumes. Two bytes is the least it can consume, and no conformant response carries fewer. The new trace point is the 129th smb_eio_trace entry, which __mode(byte) cannot represent, so the attribute goes with it.

CVSS3: 9.1
nvd
6 дней назад

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject a tree connect response whose byte count is too small CIFSTCon() bounds its strnlen() over the byte area with the server's ByteCount minus two, which for ByteCount 0 or 1 goes negative as an int and converts to a huge size_t. The later subtraction wraps the __u16 bytes_left, and that is what bounds cifs_strndup_from_utf16(): a bound of up to 65535 against a ~16 KB cifs_req_poolp object runs off the end of the slab object, and the bytes reach userspace through tcon->nativeFileSystem in /proc/fs/cifs/DebugData. Reject a byte area too small for what the parser consumes. Two bytes is the least it can consume, and no conformant response carries fewer. The new trace point is the 129th smb_eio_trace entry, which __mode(byte) cannot represent, so the attribute goes with it.

msrc
3 дня назад

smb: client: reject a tree connect response whose byte count is too small

CVSS3: 9.1
debian
6 дней назад

In the Linux kernel, the following vulnerability has been resolved: s ...

CVSS3: 9.1
github
6 дней назад

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject a tree connect response whose byte count is too small CIFSTCon() bounds its strnlen() over the byte area with the server's ByteCount minus two, which for ByteCount 0 or 1 goes negative as an int and converts to a huge size_t. The later subtraction wraps the __u16 bytes_left, and that is what bounds cifs_strndup_from_utf16(): a bound of up to 65535 against a ~16 KB cifs_req_poolp object runs off the end of the slab object, and the bytes reach userspace through tcon->nativeFileSystem in /proc/fs/cifs/DebugData. Reject a byte area too small for what the parser consumes. Two bytes is the least it can consume, and no conformant response carries fewer. The new trace point is the 129th smb_eio_trace entry, which __mode(byte) cannot represent, so the attribute goes with it.

EPSS

Процентиль: 38%
0.00448
Низкий

5.7 Medium

CVSS3