CVE-2021-33881
MEDIUM
Published Jun 6, 20215y ago · Modified Jun 17, 20262w ago
4.2 CVSS 3.1
Published Jun 6, 2021 5y ago
Last Modified Jun 17, 2026 2w ago
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 on how the anti tear-off feature is used in specific applications such as public transportation, physical access control, etc.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N Attack Vector Physical
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity High
Availability None
Threat Intelligence
No active exploitation signals — not in CISA KEV and no EPSS score yet.
Exploit & Patch Status
Public Exploit Known
No Patch Available
Weaknesses 1
CWE-863 Incorrect Authorization Authorization
Affected Products 16
| Vendor | Product | Version | Range |
|---|---|---|---|
| nxp | mifare_ultralight_ev1_firmware | * | any |
| nxp | mifare_ultralight_ev1 | * | any |
| nxp | mifare_ultralight_c_firmware | * | any |
| nxp | mifare_ultralight_c | * | any |
| nxp | mifare_ultralight_nano_firmware | * | any |
| nxp | mifare_ultralight_nano | * | any |
| nxp | ntag_210_firmware | * | any |
| nxp | ntag_210 | * | any |
| nxp | ntag_212_firmware | * | any |
| nxp | ntag_212 | * | any |
| nxp | ntag_213_firmware | * | any |
| nxp | ntag_213 | * | any |
| nxp | ntag_215_firmware | * | any |
| nxp | ntag_215 | * | any |
| nxp | ntag_216_firmware | * | any |
| nxp | ntag_216 | * | any |
References 4
- blog.quarkslab.com https://blog.quarkslab.com/rfid-monotonic-counter-anti-tearing-defeated.html
- nxp.com https://www.nxp.com/docs/en/application-note/AN11340.pdf
- nxp.com https://www.nxp.com/docs/en/application-note/AN13089.pdf
- sstic.org https://www.sstic.org/2021/presentation/eeprom_it_will_all_end_in_tears/
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.