Nettle is a cryptographic library that is designed to fit easily in almost any context: In cryptographic toolkits for object-oriented languages, such as C++, Python, or Pike, in applications like lsh or GnuPG, or even in kernel space.
It was discovered that Nettle incorrectly handled signature verification.
A remote attacker could send a specially crafted valid-looking input signature, possibly resulting in a Denial of Service condition or force an invalid signature.
There is no known workaround at this time.
All Nettle users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=dev-libs/nettle-3.7.2"