The CVE number for this vulnerability is CVE-2019-16866

== Summary
Recent versions of Unbound contain a problem that may cause Unbound to
crash after receiving a specially crafted query. This issue can only be
triggered by queries received from addresses allowed by Unbound's ACL.

== Affected products
Unbound 1.7.1 up to and including 1.9.3.

== Description
Due to an error in parsing NOTIFY queries, it is possible for Unbound to
continue processing malformed queries and may ultimately result in a
pointer dereference in uninitialized memory. This results in a crash of
the Unbound daemon.

Whether this issue leads to a crash depends on the content of the
uninitialized memory space and cannot be predicted. This issue can only
be triggered by queries received from addresses that are allowed to send
queries according to Unbound's ACL (access-control in the Unbound
configuration).

== Solution
Download patched version of Unbound, or apply the patch manually.

+ Downloading patched version
Unbound 1.9.4 is released with the patch
https://nlnetlabs.nl/downloads/unbound/unbound-1.9.4.tar.gz

+ Applying the Patch manually
For Unbound 1.7.1 up to and including 1.9.3 the patch is:
https://nlnetlabs.nl/downloads/unbound/patch_cve_2019-16866.diff

Apply the patch on Unbound source directory with:
'patch -p0 < patch_cve_2019-16866.diff'
then run 'make install' to install Unbound.

== Acknowledgments
We would like to thank X41 D-Sec for notifying us about this
vulnerability and OSTIF for sponsoring the Unbound security audit.