CVE-2021-33881: Nxp Mifare Ultralight C Firmware

Medium severity, CVSS 4.2. EPSS: 0.4% chance of exploitation in the next 30 days.

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 on how the anti tear-off feature is used in specific applications such as public transportation, physical access control, etc.

Affected products

• Nxp Mifare Ultralight C Firmware: affected versions not specified
• Nxp Mifare Ultralight EV1 Firmware: affected versions not specified
• Nxp Mifare Ultralight Nano Firmware: affected versions not specified
• Nxp Ntag 210 Firmware: affected versions not specified
• Nxp Ntag 212 Firmware: affected versions not specified
• Nxp Ntag 213 Firmware: affected versions not specified
• Nxp Ntag 215 Firmware: affected versions not specified
• Nxp Ntag 216 Firmware: affected versions not specified

Published 2021-06-06. Last modified 2026-06-17.