01 Record

CVE-2021-33881

On NXP MIFARE Ultralight and NTAG cards, an attacker can interrupt a write operation (aka conduct a "tear off" attack) over RFID to bypass a Monotonic Counter protection mechanism. The impact depends

UnratedPUBLISHEDCNA: mitre

CNA base scoreUnratedNo CNA CVSS vector

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02 Description

On NXP MIFARE Ultralight and NTAG cards, an attacker can interrupt a write operation (aka conduct a "tear off" attack) over RFID to bypass a Monotonic Counter protection mechanism. The impact depends

03 Exploitation and scoring

Exploitation: Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision: Not assessed by CISA
EPSS probability: 0.41% probability of exploitation activity in the next 30 days.
EPSS percentile: Equal to or higher than the score of 35.0% of scored records. A rank, not a probability.
NVD base score: 4.2 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD analysis status: Modified. NVD last modified this record on 2026-06-17.
Red Hat severity: No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.