Linux Kernel up to 7.3.1 smb SMB2_read DataOffset/DataLength out-of-bounds

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 7.3.1. Impacted is the function SMB2_read of the component smb. The manipulation of the argument DataOffset/DataLength results in out-of-bounds. This vulnerability is cataloged as CVE-2026-99272. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 7.3.1. Affected is the function SMB2_read of the component smb. The manipulation of the argument DataOffset/DataLength with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate the data area in SMB2_read() SMB2_read() copies le32_to_cpu(rsp->DataLength) bytes from (char *)rsp + rsp->DataOffset without checking that the range lies within the response actually received. A READ response with DataOffset == 0 makes smb2_get_data_area_len() zero the data length, so smb2_check_message() accepts a frame as short as the fixed response, while SMB2_read() still uses the server-supplied DataLength, capped only by CIFS_MAX_MSGSIZE and the caller's length. A malicious server can answer the synchronous read used by the mfsymlinks (or SFU) symlink parser with an 81-byte READ response carrying DataOffset 0 and DataLength 1067, making the client copy 1067 bytes from a 448-byte receive object (KASAN slab-out-of-bounds; up to 16 KiB in the general case). Clamp a zero (or header-overlapping) DataOffset to read_rsp_size, as handle_read_data() does for the asynchronous path, and reject the response unless DataOffset + DataLength fits within rsp_iov.iov_len. The SMB1 helper was fixed the same way in 5be5bdda5863.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-99272 since 09/25/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 11/07/2026).

Upgrading to version 7.3.2 or 7.4-rc1 eliminates this vulnerability. Applying the patch 1ba1937de005e261a8858f45bfef5da7458df94c/2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.3.0
• 7.3.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion