CVE-2026-72130 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
nvmet-auth: reject short AUTH_RECEIVE buffers
nvmet_execute_auth_receive() trusts the AUTH_RECEIVE allocation length after checking only that it is nonzero and matches the transfer length. In the SUCCESS1 and FAILURE1/default states, that lets a remote NVMe-oF initiator reach the fixed-size DH-HMAC-CHAP response builders with a kmalloc() buffer shorter than the response, so nvmet_auth_success1() and nvmet_auth_failure1() write past the allocation; both only WARN_ON the short length and then format the message anyway.
Impact: A remote NVMe-oF initiator with access to an auth-enabled target can trigger a 16-byte heap out-of-bounds write via a one-byte AUTH_RECEIVE allocation length.
Compute the minimum response length for the current DH-HMAC-CHAP step in nvmet_auth_receive_data_len() and report a zero data length when the host-supplied allocation length is shorter, so the existing zero-length check in nvmet_execute_auth_receive() rejects the command before any builder runs. The SUCCESS1 minimum is sizeof(struct nvmf_auth_dhchap_success1_data) plus the HMAC hash length, because the response hash is written into the rval[] flexible-array tail, so the
minimum is state dependent rather than a flat sizeof. CHALLENGE keeps its existing variable-length guard in nvmet_auth_challenge().
This is reachable only when in-band DH-HMAC-CHAP authentication is configured on the target.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability described represents a critical heap buffer overflow condition within the Linux kernel's NVMe over Fabrics target implementation, specifically affecting the nvme-oF authentication mechanism. This issue resides in the nvmet_auth_receive_data_len() function which computes the minimum response length for DH-HMAC-CHAP authentication steps without proper validation of the host-supplied allocation length. The flaw stems from insufficient input sanitization where the nvmet_execute_auth_receive() function initially validates that the AUTH_RECEIVE buffer allocation length is nonzero and matches the transfer length, but fails to verify that this allocated space is sufficient for the actual response data. This inadequate validation creates a path where remote attackers can manipulate the authentication flow by supplying intentionally short buffer allocations.
The technical implementation of this vulnerability exploits the trust model within the authentication state machine where the SUCCESS1 and FAILURE1 states execute without proper bounds checking against the allocated buffer size. When a malicious NVMe-oF initiator provides a one-byte allocation length for AUTH_RECEIVE commands, the system proceeds to execute nvmet_auth_success1() and nvmet_auth_failure1() functions which write beyond the allocated kmalloc() buffer boundaries. These functions only issue WARN_ON warnings for short lengths but continue processing, resulting in 16-byte heap out-of-bounds writes that can corrupt adjacent memory regions and potentially lead to arbitrary code execution or system instability.
The operational impact of this vulnerability is significant within environments utilizing NVMe-oF target implementations with in-band DH-HMAC-CHAP authentication enabled. Remote attackers who gain access to an auth-enabled target can exploit this weakness to trigger heap corruption, which may result in denial of service conditions or more severe consequences depending on the memory layout and system configuration. The vulnerability specifically affects systems where the nvme-fabrics kernel module is actively configured with authentication, making it relevant to enterprise storage environments and data center infrastructures that rely on secure NVMe-oF communication protocols.
The mitigation strategy involves implementing proper length validation within the nvmet_auth_receive_data_len() function to compute minimum response requirements based on the current DH-HMAC-CHAP authentication step. This approach ensures that when host-supplied allocation lengths are insufficient for the actual response data, the system reports zero data length which then triggers the existing zero-length validation in nvmet_execute_auth_receive() before any authentication builder functions execute. The fix specifically addresses the SUCCESS1 state minimum requirement of sizeof(struct nvmf_auth_dhchap_success1_data) plus the HMAC hash length, recognizing that this minimum is state-dependent rather than a fixed value. This solution aligns with CWE-787: Out-of-bounds Write and follows ATT&CK tactics related to privilege escalation and denial of service through memory corruption vulnerabilities. The CHALLENGE authentication step maintains its existing variable-length guard in nvmet_auth_challenge() function to preserve existing security controls while addressing the specific buffer overflow condition in the SUCCESS1 state.
This vulnerability demonstrates the critical importance of proper input validation in kernel-space authentication mechanisms, particularly when dealing with dynamic protocol implementations that require precise memory management. The fix ensures that all authentication response buffers are properly sized before any data is written, preventing the exploitation path that allows attackers to manipulate heap memory through carefully crafted authentication commands.