VulnerabilityPublished 7 Nov 2026

CVE-2026-99272: Linux kernel · smb: client: validate the data area in SMB2_read()

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1 or 1ba1937de005e261a8858f45bfef5da7458df94c soon.

Data as of 7 Nov 2026, 14:20 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1, 1ba1937de005e261a8858f45bfef5da7458df94c

Exploitation evidence

Disclosed: evidence found.
CVE published 7 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1 or 1ba1937de005e261a8858f45bfef5da7458df94c.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ d8e050398d23ef7c019c96200b80d73f4e5cec0c, < 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1	Fixed in 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1
LinuxLinux	Affected ≥ d8e050398d23ef7c019c96200b80d73f4e5cec0c, < 1ba1937de005e261a8858f45bfef5da7458df94c	Fixed in 1ba1937de005e261a8858f45bfef5da7458df94c
LinuxLinux	Affected =3.7	Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel. The vulnerability is resolved by clamping invalid DataOffset values and validating that the read length fits within the received response buffer. Users should update to the fixed Linux kernel versions identified by the commits 2ec9cdf469dd32bcf33073aeb30c08e9356e0ca1 and 1ba1937de005e261a8858f45bfef5da7458df94c.

Description

A vulnerability in the Linux kernel SMB client implementation in SMB2_read() allows a malicious SMB server to cause out-of-bounds memory reads by sending a crafted READ response with inconsistent DataOffset and DataLength values. This flaw can lead to copying more data than the actual response size, potentially causing memory corruption or information disclosure. The issue has been fixed by validating and clamping the DataOffset and ensuring the total read length fits within the received response buffer.

Impact

A malicious SMB server can exploit this vulnerability to cause out-of-bounds memory reads in the Linux kernel SMB client, potentially leading to memory corruption or information disclosure. The flaw affects the SMB2 protocol implementation and could be triggered during symlink parsing operations. There is no indication of known exploits in the wild.

Summary

The Linux kernel SMB client had a vulnerability in the SMB2_read() function where it copied DataLength bytes from an offset in the response without verifying that the data range was within the actual received response buffer. Specifically, if a malicious server sent a READ response with DataOffset set to zero and a large DataLength, the client could copy more bytes than were actually received, leading to a slab-out-of-bounds read. This was exploitable via the synchronous read used by the mfsymlinks or SFU symlink parser. The fix clamps zero or overlapping DataOffset values and rejects responses where DataOffset plus DataLength exceed the response buffer length, aligning SMB2_read() behavior with the asynchronous path and the SMB1 helper fix.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 7 Nov 2026, 14:20 UTC

Technical details

References

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