CVE-2026-23354
Linux Kernel 6.9.1 – 6.12.77
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-23354 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 3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-23354 is a vulnerability in the Linux kernel's x86/fred component, specifically within the fred_extint() function. The issue stems from incorrect usage of array_index_nospec() for speculative safety, where the index value is spilled to the stack across an irqentry_enter() call, making it vulnerable to memory predictions. This violates the requirement that array_index_nospec() must be used directly in the array access expression. The flaw is classified under CWE-129 (Improper Validation of Array Index) with a CVSS v3.1 base 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 with low complexity and no user interaction required. Successful exploitation could result in high impacts to confidentiality, integrity, and availability, potentially allowing unauthorized data access, modification, or denial of service through speculative execution leading to improper array indexing.
Mitigation involves applying the upstream kernel patches provided in the referenced stable commits, including 3bc5887b0a2b06d2d9c22f1f4f8500490b3ae643, 92caa5274b99cb6729177232a029ce0dfa6c5f7b, aa280a08e7d8fae58557acc345b36b3dc329d595, and e58f1a9b0677de24dcfee0b21393446ec92ff120, which reposition array_index_nospec() immediately before the array access and remove the intermediate index variable. Security practitioners should update affected Linux kernel installations to versions incorporating these fixes.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-15329
Vulnerability Data
In the Linux kernel, the following vulnerability has been resolved: x86/fred: Correct speculative safety in fred_extint() array_index_nospec() is no use if the result gets spilled to the stack, as it makes the believed safe-under-speculation value subject to memory predictions. For…
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all practical purposes, this means array_index_nospec() must be used in the expression that accesses the array. As the code currently stands, it's the wrong side of irqentry_enter(), and 'index' is put into %ebp across the function call. Remove the index variable and reposition array_index_nospec(), so it's calculated immediately before the array access.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input validation and bounds checking that prevent improper array indexing.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect out-of-bounds array access but does not prevent the weakness by itself.
Secure development lifecycle mandates input validation and bounds checking that directly prevents improper array indexing.
Application security requirements include validation of untrusted input used for indexing or addressing memory structures.
Secure architecture principles encourage defensive coding patterns that reduce index-related vulnerabilities.
Secure coding standards explicitly require bounds checking and validation of array indices derived from untrusted data.