CVE-2023-40271

Name: CVE-2023-40271
Creator: NVD / NIST
Published: 2023-09-08T02:15:08.133+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.32%

Last modified Jun 17, 2026

CVE-2023-40271 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In Trusted Firmware-M through TF-Mv1.8.0, for platforms that integrate the CryptoCell accelerator, when the CryptoCell PSA Driver software Interface is selected, and the Authenticated Encryption with Associated Data Chacha20-Poly1305 algorithm is used, with the single-part verification function (defined during the build-time configuration phase) implemented with a dedicated function (i.e., not relying on usage of multipart functions), the buffer comparison during the verification of the authentication tag does not happen on the full 16 bytes but just on the first 4 bytes, thus leading to the possibility that unauthenticated payloads might be identified as authentic. This affects TF-Mv1.6.0, TF-Mv1.6.1, TF-Mv1.7.0, and TF-Mv1.8.. EPSS estimates a 0.32% chance of exploitation in the next 30 days.

Description

In Trusted Firmware-M through TF-Mv1.8.0, for platforms that integrate the CryptoCell accelerator, when the CryptoCell PSA Driver software Interface is selected, and the Authenticated Encryption with Associated Data Chacha20-Poly1305 algorithm is used, with the single-part verification function (defined during the build-time configuration phase) implemented with a dedicated function (i.e., not relying on usage of multipart functions), the buffer comparison during the verification of the authentication tag does not happen on the full 16 bytes but just on the first 4 bytes, thus leading to the possibility that unauthenticated payloads might be identified as authentic. This affects TF-Mv1.6.0, TF-Mv1.6.1, TF-Mv1.7.0, and TF-Mv1.8.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

0.32%

24.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-697

Affected Software

Vendor	Product	Versions
Trustedfirmware	Trusted Firmware-M	1.6.0
Trustedfirmware	Trusted Firmware-M	1.6.1
Trustedfirmware	Trusted Firmware-M	1.7.0
Trustedfirmware	Trusted Firmware-M	1.8.0

References

https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/security/security_advisories/cc3xx_partial_tag_compare_on_chacha20_poly1305.rstExploit, Mitigation, Technical Description, Vendor Advisory
https://tf-m-user-guide.trustedfirmware.org/releases/index.htmlRelease Notes
https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/security/security_advisories/cc3xx_partial_tag_compare_on_chacha20_poly1305.rstExploit, Mitigation, Technical Description, Vendor Advisory
https://tf-m-user-guide.trustedfirmware.org/releases/index.htmlRelease Notes

Timeline

Published: Sep 8, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-40271?

How severe is CVE-2023-40271?

CVE-2023-40271 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.32% probability of exploitation in the next 30 days.

How do I fix CVE-2023-40271?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-40271?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST