Bug 2460696 (CVE-2026-31512)

Summary: CVE-2026-31512 kernel: Bluetooth: L2CAP: Validate PDU length before reading SDU length in l2cap_ecred_data_rcv()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Bluetooth L2CAP (Logical Link Control and Adaptation Protocol) component. The l2cap_ecred_data_rcv() function fails to validate the incoming data packet unit (PDU) length before attempting to read the Service Data Unit (SDU) length. This oversight allows an attacker to craft a malicious packet that, when processed, can cause the system to read beyond the allocated buffer, potentially leading to information disclosure or a denial of service.
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Description OSIDB Bzimport 2026-04-22 15:06:02 UTC 
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: L2CAP: Validate PDU length before reading SDU length in l2cap_ecred_data_rcv()

l2cap_ecred_data_rcv() reads the SDU length field from skb->data using
get_unaligned_le16() without first verifying that skb contains at least
L2CAP_SDULEN_SIZE (2) bytes. When skb->len is less than 2, this reads
past the valid data in the skb.

The ERTM reassembly path correctly calls pskb_may_pull() before reading
the SDU length (l2cap_reassemble_sdu, L2CAP_SAR_START case). Apply the
same validation to the Enhanced Credit Based Flow Control data path.
Comment 1 Keith Grant 2026-04-22 19:53:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042209-CVE-2026-31512-b386@gregkh/T