Vulnerability Database

374,559

Total vulnerabilities in the database

CVE-2026-31513 — linux / linux_kernel

Out-of-bounds Read

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

Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req

Syzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd() that is triggered by a malformed Enhanced Credit Based Connection Request.

The vulnerability stems from l2cap_ecred_conn_req(). The function allocates a local stack buffer (pdu) designed to hold a maximum of 5 Source Channel IDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more than 5 SCIDs, the function calculates rsp_len based on this unvalidated cmd_len before checking if the number of SCIDs exceeds L2CAP_ECRED_MAX_CID.

If the SCID count is too high, the function correctly jumps to the response label to reject the packet, but rsp_len retains the attacker's oversized value. Consequently, l2cap_send_cmd() is instructed to read past the end of the 18-byte pdu buffer, triggering a KASAN panic.

Fix this by moving the assignment of rsp_len to after the num_scid boundary check. If the packet is rejected, rsp_len will safely remain 0, and the error response will only read the 8-byte base header from the stack.

  • Published: Apr 22, 2026
  • Updated: Apr 28, 2026
  • CVE: CVE-2026-31513
  • Severity: High
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: High
  • Score: 8.1
  • AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CWEs:

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CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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