Home/CVE/In Trusted Firmware-M through TF-Mv1.8.0, for platforms that integrate the CryptoCell accelerator, when the CryptoCell P
CVE
CVE-2023-40271
In Trusted Firmware-M through TF-Mv1.8.0, for platforms that integrate the CryptoCell accelerator, when the CryptoCell P
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.
HIGH · CVSS 7.5
EPSS 0.0019
Act now
- Public exploit or PoC is available
- SSVC automatable: yes - attacks can be scripted at scale
- CVSS base score ≥ 7.0
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2023-40271, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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ATT&CK techniques
1Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-10 · Buffer Overflow via Environment Variables CAPEC-CAPEC-120 · Double Encoding CAPEC-CAPEC-14 · Client-side Injection-induced Buffer Overflow CAPEC-CAPEC-15 · Command Delimiters CAPEC-CAPEC-182 · Flash Injection CAPEC-CAPEC-24 · Filter Failure through Buffer Overflow CAPEC-CAPEC-267 · Leverage Alternate Encoding CAPEC-CAPEC-3 · Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-CAPEC-41 · Using Meta-characters in E-mail Headers to Inject Malicious Payloads CAPEC-CAPEC-43 · Exploiting Multiple Input Interpretation Layers CAPEC-CAPEC-44 · Overflow Binary Resource File CAPEC-CAPEC-45 · Buffer Overflow via Symbolic Links
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Weakness Classification
CWE-697Incorrect Comparison
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Affected Products & Versions
2arm trusted firmware-mall versions
trustedfirmware trusted firmware-mall versions
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Public Exploits & PoCs
2These PoC and exploit links come from public sources and are not verified to be safe or functional. Review the code before running anything, and treat unverified entries as untrusted.
pocgit.trustedfirmware.org · cc3xx_partial_tag_compare_on_chacha20_poly1305.rstgit.trustedfirmware.org
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Scoring & Timeline
7.5
HIGH · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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References & Sources
1Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.