Yubico libu2f-host 1.1.6 contains unchecked buffers in devs.c, which could enable a malicious token to exploit a buffer overflow. An attacker could use this to attempt to execute malicious code using a crafted USB device masquerading as a security token on a computer where the affected library is currently in use. It is not possible to perform this attack with a genuine YubiKey.

yubico · debian

In devs.c in Yubico libu2f-host before 1.1.8, the response to init is misparsed, leaking uninitialized stack memory back to the device.

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An out-of-bounds read issue was discovered in the Yubico-Piv 1.5.0 smartcard driver. The file lib/ykpiv.c contains the following code in the function `_ykpiv_fetch_object()`: {% highlight c %} if(sw == SW_SUCCESS) { size_t outlen; int offs = _ykpiv_get_length(data + 1, &outlen); if(offs == 0) { return YKPIV_SIZE_ERROR; } memmove(data, data + 1 + offs, outlen); *len = outlen; return YKPIV_OK; } else { return YKPIV_GENERIC_ERROR; } {% endhighlight %} -- in the end, a `memmove()` occurs with a length retrieved from APDU data. This length is not checked for whether it is outside of the APDU data retrieved. Therefore the `memmove()` could copy bytes behind the allocated data buffer into this buffer.

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