GHSA-f366-4rvv-95x2
GHSA-f366-4rvv-95x2 is a security vulnerability in cryptoauthlib. O3 Security confirms whether GHSA-f366-4rvv-95x2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Buffer overflow in deprecated USB HALs and stack overflow in USB enumeration
Real-World Exposure
cryptoauthlibReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
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If an application is making use of the deprecated kit protocol HALs as the communication channel to the target device an attacker can masquerade as a device and return malformed packets of arbitrary length which the protocol stack will write to the stack. HALs intended for production use are unaffected (I2C, SWI, & SPI) as well as the hidapi HAL (hal_all_platforms_kit_hidapi.c).
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The hidapi HAL can be made to overrun the application stack by attaching more than 10 (real or virtual) devices likely resulting in an application crash as this does not allow arbitrary data to be written to the stack.
Patches
USB kit enumeration has been patched in v3.2.3 for the hidapi HAL (hal_all_platforms_kit_hidapi.c).
Removal of deprecated HALs
Deprecated usb kit HALs have been removed in v3.2.3.
Workarounds
This vulnerability is limited to users of the kit protocol which is used with Microchip kits and kit firmware to bridge communication from USB-HID to I2C or SWI. It is not expected that kits would be used in an production environment. This is an optional component for users as well so they can always compile the library without the usb support option.
Special python packaging notes
The python package for cryptoauthlib uses date codes for identifying versions. The patched version for python packages is 20200912
References
Please see Microchip PSIRT for Microchip's security policy and reporting procedures
Credits
Special thanks to Ruben Santamarta of IOActive for reporting
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cryptoauthlib | all versions | 20200912 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cryptoauthlib. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update cryptoauthlib to 20200912 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f366-4rvv-95x2 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-f366-4rvv-95x2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-f366-4rvv-95x2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-f366-4rvv-95x2 in your dependencies?
O3 detects GHSA-f366-4rvv-95x2 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.