CVE-2026-97563 Linux CVE debrief

Who should care

Linux kernel developers, administrators who use SMB1 protocol, security teams, and vulnerability management teams responsible for Linux systems, as well as operators and platform maintainers who need to ensure the security and integrity of their Linux-based infrastructure.

Why it matters

A vulnerability in the Linux kernel's SMB1 synchronous read helper CIFSSMBRead() has been resolved, potentially allowing information disclosure or denial of service. Linux kernel developers and administrators who use SMB1 protocol should review and apply the patch, verify SMB1 is not negotiated by default, and monitor for potential exploitation attempts.

• Potential information disclosure
• Potential denial of service (crash or oops)
• Verification of SMB1 protocol usage and patch application required
• Monitoring for potential exploitation attempts recommended

Technical summary

The Linux kernel's SMB1 synchronous read helper CIFSSMBRead() does not validate the server's DataOffset, allowing a malicious or compromised SMB1 server to return a response that drives the source pointer past the end of the response buffer, potentially disclosing information or causing a denial of service. This issue can be mitigated by reviewing and applying the patch, verifying SMB1 is not negotiated by default, and monitoring for potential exploitation attempts. The vulnerability was discovered in the Linux kernel's SMB1 synchronous read helper CIFSSMBRead().

Defensive priority

Medium

Recommended defensive actions

• Review and apply the patch to the Linux kernel
• Verify SMB1 is not negotiated by default and ensure explicit vers=1.0 mount is not used
• Monitor for potential information disclosure or denial of service
• Perform vulnerability scanning to identify potentially affected systems
• Review system logs for suspicious activity related to SMB1
• Implement compensating controls for exposed systems
• Track exceptions and retest remediated assets

Evidence notes

The vulnerability was discovered in the Linux kernel's SMB1 synchronous read helper CIFSSMBRead(). The CVE record and NVD entry provide details on the vulnerability, but no additional information on exploitation or impact is available.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.