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Fencer Vulns
high 7.5

CVE-2023-40271 json

In Trusted Firmware-M through TF-Mv1.8.0, for platforms that integrate the CryptoCell accelerator, when the CryptoCell PSA Driver software…

published 2023-09-08 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-44867

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

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.

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • git.trustedfirmware.org https://git.trustedfirmware.org/TF-M/trusted-firmware-m.git/tree/docs/security/security_advisories/cc3xx_partial_tag_compare_on_chacha20_poly1305.rst referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.