{"cve":"CVE-2021-33881","nvd":{"published":"2021-06-06T16:15:07.407","modified":"2026-06-17T03:55:19.630","status":"Modified","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N","score":4.2},"cwes":["CWE-863"],"references":["https://blog.quarkslab.com/rfid-monotonic-counter-anti-tearing-defeated.html","https://www.nxp.com/docs/en/application-note/AN11340.pdf","https://www.nxp.com/docs/en/application-note/AN13089.pdf","https://www.sstic.org/2021/presentation/eeprom_it_will_all_end_in_tears/","https://blog.quarkslab.com/rfid-monotonic-counter-anti-tearing-defeated.html"],"products":["nxp:mifare_ultralight_c_firmware","nxp:mifare_ultralight_ev1_firmware","nxp:mifare_ultralight_nano_firmware","nxp:ntag_210_firmware","nxp:ntag_212_firmware","nxp:ntag_213_firmware","nxp:ntag_215_firmware","nxp:ntag_216_firmware"],"source":"nvd","synced_at":"2026-10-19T21:20:07.141963181+00:00"},"epss":{"cve":"CVE-2021-33881","score":0.00411,"percentile":0.35375,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}