A security-related issue has been reported in Go's math/big
package. The issue was introduced in Go 1.5. We recommend that all
users upgrade to Go 1.5.3, which fixes the issue. Go programs must
be recompiled with Go 1.5.3 in order to receive the fix.
The Go team would like to thank Nick Craig-Wood for identifying the
This issue can affect RSA computations in crypto/rsa, which is used
by crypto/tls. TLS servers on 32-bit systems could plausibly leak
their RSA private key due to this issue. Other protocol
implementations that create many RSA signatures could also be
impacted in the same way.
Specifically, incorrect results in one part of the RSA Chinese
Remainder computation can cause the result to be incorrect in such a
way that it leaks one of the primes. While RSA blinding should
prevent an attacker from crafting specific inputs that trigger the
bug, on 32-bit systems the bug can be expected to occur at random
around one in 2^26 times. Thus collecting around 64 million
signatures (of known data) from an affected server should be enough
to extract the private key used.
On 64-bit systems, the frequency of the bug is so low (less than
one in 2^50) that it would be very difficult to exploit.
Nonetheless, everyone is strongly encouraged to upgrade.