Raw vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-31622 is a high-severity Classic Buffer Overflow (CWE-120) vulnerability in Linux Linux Kernel. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 20th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
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-2026-31622 is a buffer overflow vulnerability in the Linux kernel's NFC digital subsystem, specifically in the NFC-A anti-collision cascade handling within the digital_in_recv_sdd_res() function. The vulnerability arises because the function appends 3 or 4 bytes to the target->nfcid1 field on each cascade round, with the number of rounds and byte lengths controlled entirely by the peer device via the cascade tag in SDD_RES and the cascade-incomplete bit in SEL_RES. Although ISO 14443-3 limits NFC-A to three cascade levels and the nfcid1 buffer is sized to NFC_NFCID1_MAXSIZE (10 bytes), the driver lacks enforcement, allowing a malicious peer to extend the cascade indefinitely and overwrite memory past the heap-allocated nfc_target structure. The issue is scored at CVSS 8.8 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) and maps to CWE-120.
A malicious NFC peer device within adjacent physical proximity (NFC range) can exploit this vulnerability with low complexity, no privileges, and no user interaction required. By manipulating the cascade tags and incomplete bits in responses, the attacker triggers repeated appendages to nfcid1, causing a heap-based buffer overflow. This can lead to high-impact confidentiality, integrity, and availability violations, such as remote code execution, data corruption, or denial of service via kernel crash.
The provided references point to Linux kernel stable branch commit patches that mitigate the issue by adding bounds checks in digital_in_recv_sdd_res() to reject SDD responses when the accumulated UID would exceed the nfcid1 buffer size. These commits (e.g., 1bec5698b55aa2be5c3b983dba657c01d0fd3dbc) align with a prior fix in commit e329e71013c9 for similar unchecked bounds on the NCI path, recommending kernel updates to stable versions incorporating these changes.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25515
Vulnerability Data
In the Linux kernel, the following vulnerability has been resolved: NFC: digital: Bounds check NFC-A cascade depth in SDD response handler The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3 or 4 bytes to target->nfcid1 on each round, but the number…
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of cascade rounds is controlled entirely by the peer device. The peer sets the cascade tag in the SDD_RES (deciding 3 vs 4 bytes) and the cascade-incomplete bit in the SEL_RES (deciding whether another round follows). ISO 14443-3 limits NFC-A to three cascade levels and target->nfcid1 is sized accordingly (NFC_NFCID1_MAXSIZE = 10), but nothing in the driver actually enforces this. This means a malicious peer can keep the cascade running, writing past the heap-allocated nfc_target with each round. Fix this by rejecting the response when the accumulated UID would exceed the buffer. Commit e329e71013c9 ("NFC: nci: Bounds check struct nfc_target arrays") fixed similar missing checks against the same field on the NCI path.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.2.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and analysis can find missing size checks before deployment.
Input validation directly enforces size checks before buffer copies.
Engineering principles require bounds checking and safe buffer handling in design.
Memory protection limits the impact of an overflow once it occurs.
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 development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.
Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.
Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.
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.
Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.
Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.
Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.
Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.
Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.