CVE-2022-49807 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
nvmet: fix a memory leak in nvmet_auth_set_key
When changing dhchap secrets we need to release the old secrets as well.
kmemleak complaint: -- unreferenced object 0xffff8c7f44ed8180 (size 64): comm "check", pid 7304, jiffies 4295686133 (age 72034.246s) hex dump (first 32 bytes): 44 48 48 43 2d 31 3a 30 30 3a 4c 64 4c 4f 64 71 DHHC-1:00:LdLOdq 79 56 69 67 77 48 55 32 6d 5a 59 4c 7a 35 59 38 yVigwHU2mZYLz5Y8 backtrace: [<00000000b6fc5071>] kstrdup+0x2e/0x60
[<00000000f0f4633f>] 0xffffffffc0e07ee6
[<0000000053006c05>] 0xffffffffc0dff783
[<00000000419ae922>] configfs_write_iter+0xb1/0x120
[<000000008183c424>] vfs_write+0x2be/0x3c0
[<000000009005a2a5>] ksys_write+0x5f/0xe0
[<00000000cd495c89>] do_syscall_64+0x38/0x90
[<00000000f2a84ac5>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
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Analysis
by VulDB Data Team • 11/07/2025
The vulnerability CVE-2022-49807 represents a memory leak in the Linux kernel's NVMe over Fabrics target implementation, specifically within the nvmet_auth_set_key function. This issue occurs during dynamic modification of Diffie-Hellman Challenge-Handshake Authentication Protocol (DHCHAP) secrets, which are critical for securing NVMe fabric communications. The flaw demonstrates a classic memory management error where allocated kernel memory is not properly released when updating authentication credentials, creating a persistent memory leak that can accumulate over time and potentially impact system stability.
The technical root cause stems from inadequate resource cleanup in the nvmet subsystem's authentication handling code. When DHCHAP secrets are updated through configuration file operations, the existing secret data structures are not properly deallocated before new ones are assigned. This memory leak manifests as unreferenced kernel objects that remain allocated in memory even after the authentication context has been modified, as evidenced by the kmemleak diagnostic output showing a 64-byte object with the hexadecimal content representing typical DHCHAP secret data. The backtrace reveals the memory allocation path originating from kstrdup function calls, indicating that string duplication operations during authentication secret processing fail to properly release previous allocations.
The operational impact of this vulnerability extends beyond simple memory consumption, as persistent memory leaks in kernel space can degrade system performance and potentially lead to resource exhaustion under sustained attack conditions. Attackers could exploit this weakness by repeatedly modifying authentication secrets, causing progressive memory consumption that might eventually lead to system instability or denial of service conditions. The vulnerability specifically affects systems running NVMe over Fabrics target implementations, making it particularly relevant for enterprise storage environments and data center infrastructure where NVMe fabrics are deployed. The memory leak could be particularly problematic in high-traffic scenarios where frequent authentication updates occur, as the accumulated leaked memory would progressively reduce available system resources.
Mitigation strategies should focus on implementing proper memory management practices in kernel code, ensuring that all allocated resources are properly released during authentication secret updates. System administrators should prioritize applying kernel updates that contain the patched nvmet implementation, which correctly handles memory deallocation during DHCHAP secret modifications. The fix addresses the underlying CWE-401 vulnerability category related to improper resource management, aligning with ATT&CK technique T1547.001 for privilege escalation through kernel-level memory corruption. Organizations should also implement monitoring for memory usage patterns in NVMe target systems and consider implementing automated alerts for unusual memory consumption that might indicate memory leak exploitation attempts. Regular kernel security updates and proper system hardening practices remain essential defensive measures against similar memory management vulnerabilities in kernel space.