CVE-2026-31538 Vulnerability Analysis & Exploit Details

CVE-2026-31538
Vulnerability Scoring

7.5
/10
Very High Risk

Highly exploitable, CVE-2026-31538 poses a critical security risk that could lead to severe breaches.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-31538 Details

Status: Analyzed

Last updated: 🕡 28 Apr 2026, 18:59 UTC
Originally published on: 🕒 24 Apr 2026, 15:16 UTC

Time between publication and last update: 4 days

CVSS Release: version 3

CVSS3 Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE-2026-31538 Vulnerability Summary

CVE-2026-31538: In the Linux kernel, the following vulnerability has been resolved: smb: server: make use of smbdirect_socket.recv_io.credits.available The logic off managing recv credits by counting posted recv_io and granted credits is racy. That's because the peer might already consumed a credit, but between receiving the incoming recv at the hardware and processing the completion in the 'recv_done' functions we likely have a window where we grant credits, which don't really exist. So we better have a decicated counter for the available credits, which will be incremented when we posted new recv buffers and drained when we grant the credits to the peer. This fixes regression Namjae reported with the 6.18 release.

Assessing the Risk of CVE-2026-31538

Access Complexity Graph

The exploitability of CVE-2026-31538 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-31538

With low attack complexity and no required privileges, CVE-2026-31538 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-31538, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-31538, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2026-31538 has no significant impact on data confidentiality.
  • Integrity: None
    CVE-2026-31538 poses no threat to data integrity.
  • Availability: High
    CVE-2026-31538 can disrupt system operations, potentially causing complete denial of service (DoS).

CVE-2026-31538 References

External References

CWE Common Weakness Enumeration

NVD-CWE-Other

Vulnerable Configurations

  • cpe:2.3:o:linux:linux_kernel:6.18:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18:-:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.1:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.1:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.2:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.2:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.3:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.3:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.4:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.5:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.5:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.6:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.6:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.7:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.7:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.8:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.8:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.9:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.9:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.18.10:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.18.10:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*

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