CVE-2023-53000
Published: 27 March 2025
Summary
CVE-2023-53000 is a high-severity Improper Validation of Array Index (CWE-129) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 7.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2023-53000 is a vulnerability in the Linux kernel's netlink subsystem that enables potential Spectre v1 gadgets. During netlink attribute parsing in functions like __nla_validate_parse() or validate_nla(), the attribute type is extracted as a u16 and validated against maxtype, but its subsequent use as an array index lacks protection against speculative execution. This allows the type value to serve as a Spectre v1 gadget, potentially leaking kernel memory contents to malicious users. The issue is classified under CWE-129 (Improper Validation of Array Index) with a CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
A local attacker with low privileges can exploit this vulnerability by crafting malicious netlink messages that trigger the unprotected array indexing during parsing. Successful exploitation relies on Spectre v1 speculative execution to access out-of-bounds kernel memory, enabling information disclosure. The high CVSS impacts reflect potential for significant confidentiality loss, along with integrity and availability disruptions from the resulting kernel state corruption or denial of service.
Mitigation requires updating to patched Linux kernel versions incorporating the referenced stable commits, such as 3e5082b1c66c7783fbcd79b5b178573230e528ff, 41b74e95f297ac360ca7ed6bf200100717cb6c45, 539ca5dcbc91134bbe2c45677811c31d8b030d2d, 992e4ff7116a77968039277b5d6aaa535c2f2184, and f0950402e8c76e7dcb08563f1b4e8000fbc62455. These patches insert array_index_nospec() barriers to prevent the gadgets in most netlink parsing paths, though the fix recommends a broader audit for non-centralized validation cases.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-59720
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: netlink: prevent potential spectre v1 gadgets Most netlink attributes are parsed and validated from __nla_validate_parse() or validate_nla() u16 type = nla_type(nla); if (type == 0 || type > maxtype) {…
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/* error or continue */ } @type is then used as an array index and can be used as a Spectre v1 gadget. array_index_nospec() can be used to prevent leaking content of kernel memory to malicious users. This should take care of vast majority of netlink uses, but an audit is needed to take care of others where validation is not yet centralized in core netlink functions.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel vulnerability enabling speculative memory disclosure and potential state corruption/DoS, which can be exploited for privilege escalation or credential access.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Flaw remediation directly mitigates CVE-2023-53000 by applying kernel patches that insert array_index_nospec() barriers to prevent Spectre v1 gadgets in netlink parsing.
Memory protection techniques prevent unauthorized kernel memory disclosure through speculative execution attacks like the Spectre v1 gadget in netlink attribute type indexing.
Information input validation ensures netlink attribute types are properly checked before array indexing, addressing the improper validation that enables the Spectre v1 gadget.