CVE-2021-33881

Public Exploit

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.

Category

4.2
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.06%
Vendor Advisory nxp.com Vendor Advisory nxp.com
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://blog.quarkslab.com/rfid-monotonic-counter-anti-tearing-defeated.html third party advisory mitigation
https://www.nxp.com/docs/en/application-note/AN13089.pdf vendor advisory
https://www.nxp.com/docs/en/application-note/AN11340.pdf vendor advisory
https://www.sstic.org/2021/presentation/eeprom_it_will_all_end_in_tears/ third party advisory exploit

Frequently Asked Questions

What is the severity of CVE-2021-33881?
CVE-2021-33881 has been scored as a medium severity vulnerability.
How to fix CVE-2021-33881?
To fix CVE-2021-33881, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-33881 being actively exploited in the wild?
It is possible that CVE-2021-33881 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.