CVE-2022-49862 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
tipc: fix the msg->req tlv len check in tipc_nl_compat_name_table_dump_header
This is a follow-up for commit 974cb0e3e7c9 ("tipc: fix uninit-value in tipc_nl_compat_name_table_dump") where it should have type casted sizeof(..) to int to work when TLV_GET_DATA_LEN() returns a negative value.
syzbot reported a call trace because of it:
BUG: KMSAN: uninit-value in ... tipc_nl_compat_name_table_dump+0x841/0xea0 net/tipc/netlink_compat.c:934 __tipc_nl_compat_dumpit+0xab2/0x1320 net/tipc/netlink_compat.c:238 tipc_nl_compat_dumpit+0x991/0xb50 net/tipc/netlink_compat.c:321 tipc_nl_compat_recv+0xb6e/0x1640 net/tipc/netlink_compat.c:1324 genl_family_rcv_msg_doit net/netlink/genetlink.c:731 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
genl_rcv_msg+0x103f/0x1260 net/netlink/genetlink.c:792 netlink_rcv_skb+0x3a5/0x6c0 net/netlink/af_netlink.c:2501 genl_rcv+0x3c/0x50 net/netlink/genetlink.c:803 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0xf3b/0x1270 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x1288/0x1440 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
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Analysis
by VulDB Data Team • 03/14/2026
The vulnerability CVE-2022-49862 affects the Linux kernel's TIPC (Transparent Inter-Process Communication) subsystem, specifically within the netlink compatibility layer responsible for name table dumping operations. This issue represents a critical uninitialized value access that can lead to kernel memory corruption and potential system instability. The vulnerability manifests when processing TLV (Type-Length-Value) data structures during network name resolution operations, where the kernel fails to properly handle negative return values from TLV_GET_DATA_LEN() macro. The flaw was identified through automated fuzzing by syzbot, which detected a kernel memory sanitizer (KMSAN) warning indicating uninitialized memory access patterns.
The technical root cause lies in the improper type casting of sizeof() operations within the tipc_nl_compat_name_table_dump_header function, where the fix implemented in commit 974cb0e3e7c9 attempted to address uninitialized value issues but failed to account for the specific case where TLV_GET_DATA_LEN() can return negative values. When this occurs, the subsequent arithmetic operations with uninitialized memory variables create a path for kernel memory corruption that can be exploited through malicious network packets or crafted kernel module interactions. The call trace demonstrates the execution path leading to the bug through the TIPC netlink compatibility layer, specifically highlighting the tipc_nl_compat_name_table_dump function at line 934 where the uninitialized memory access occurs. This vulnerability operates at the kernel level and can be triggered through legitimate network communication protocols, making it particularly dangerous as it may not require elevated privileges to exploit.
The operational impact of CVE-2022-49862 extends beyond simple memory corruption, potentially enabling denial-of-service conditions or privilege escalation attacks depending on the specific exploitation vector. Attackers could leverage this vulnerability to crash kernel subsystems, cause system instability, or in more sophisticated scenarios potentially execute arbitrary code within kernel space. The vulnerability affects systems running Linux kernels with TIPC support, particularly those utilizing network name resolution services or applications that depend on TIPC for inter-process communication. From an ATT&CK framework perspective, this vulnerability maps to T1068 (Exploitation for Privilege Escalation) and T1499 (Endpoint Detection and Removal) categories, as it represents a kernel-level exploit that could be used to gain elevated privileges or disrupt system operations. The vulnerability also aligns with CWE-457 (Use of Uninitialized Variable) and CWE-125 (Out-of-Bounds Read) categories, which are fundamental security weaknesses in kernel space programming.
Mitigation strategies for CVE-2022-49862 should prioritize immediate kernel updates from trusted sources, as the vulnerability has been patched in subsequent kernel releases. Organizations should implement network segmentation to limit TIPC protocol exposure, disable unnecessary TIPC services, and monitor for unusual network activity patterns that might indicate exploitation attempts. System administrators should also consider deploying kernel hardening measures such as KASLR (Kernel Address Space Layout Randomization) and SMEP/SMAP (Supervisor Mode Execution Prevention/Supervisor Mode Access Prevention) to limit the impact of potential exploitation. Additionally, implementing network intrusion detection systems with signatures for TIPC protocol anomalies can help detect early exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper type handling and memory management in kernel space code, emphasizing the need for comprehensive testing and validation of kernel subsystems against various input conditions and edge cases.