CVE-2022-49293 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: initialize registers in nft_do_chain()
Initialize registers to avoid stack leak into userspace.
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Analysis
by VulDB Data Team • 10/21/2025
The vulnerability identified as CVE-2022-49293 represents a critical stack information disclosure issue within the Linux kernel's netfilter subsystem, specifically affecting the nftables framework. This flaw exists in the nft_do_chain() function where registers are not properly initialized before being used in packet processing operations. The vulnerability falls under the category of information disclosure through stack leakage, which can potentially expose sensitive kernel memory contents to unprivileged userspace processes. The issue arises from improper memory management during the execution of netfilter chains, creating a pathway for attackers to harvest kernel stack data that should remain confidential.
The technical implementation of this vulnerability stems from the nftables subsystem's handling of register initialization within the nft_do_chain() function. When processing network packets through netfilter chains, the kernel fails to properly zero out or initialize register values before utilizing them in subsequent operations. This initialization gap creates a scenario where residual stack data from previous operations or uninitialized memory regions may be inadvertently exposed to userspace applications. The flaw specifically impacts the nf_tables subsystem which provides the userspace interface for configuring netfilter rules, making it particularly concerning for systems that rely heavily on network filtering and packet manipulation. This issue directly relates to CWE-248, which addresses the exposure of uninitialized variables, and represents a classic example of information disclosure through memory leakage.
The operational impact of CVE-2022-49293 extends beyond simple information disclosure, as the leaked stack data could potentially contain sensitive kernel memory structures, cryptographic keys, or other confidential information that might aid in further exploitation attempts. Attackers could leverage this vulnerability to gather intelligence about the kernel's memory layout, potentially facilitating more sophisticated attacks such as privilege escalation or bypassing security mechanisms. The vulnerability is particularly dangerous in environments where multiple unprivileged users share the same system, as each user could potentially access information from other users' kernel memory contexts. This weakness could also be exploited as part of a broader attack chain, where the leaked information serves as a foundation for more advanced exploitation techniques, making it a significant concern for system administrators managing critical infrastructure.
Mitigation strategies for CVE-2022-49293 primarily focus on applying the official kernel patches that properly initialize registers within the nft_do_chain() function. System administrators should prioritize updating their Linux kernel installations to versions that include the fix, which typically involves ensuring that register values are properly zeroed before being used in packet processing operations. Additionally, implementing network segmentation and access controls can help limit the potential impact of information disclosure, while monitoring for unusual network traffic patterns or privilege escalation attempts can provide early detection of exploitation attempts. Organizations should also consider implementing the principle of least privilege for users accessing netfilter functionality and regularly audit their nftables configurations to minimize exposure. The fix addresses the underlying memory initialization issue through proper stack management practices, aligning with established security guidelines for kernel development and system hardening measures recommended by organizations such as the Center for Internet Security and the National Institute of Standards and Technology.