See <https://soatok.blog/2024/08/14/security-issues-in-matrixs-olm-library/>.

(cherry picked from commit e4767b4)

These vendor the libolm code.

(cherry picked from commit bbfd5d1)

CVE numbers were assigned, and This Week in Matrix included an
announcement from the Matrix.org project lead. An official post from
the Matrix.org Foundation is apparently still pending.

(cherry picked from commit 069f7de)

Additional information has been published by upstream about why they
believe the vulnerability to not be exploitable over the network:
https://matrix.org/blog/2024/08/libolm-deprecation/

This commit

* updates the text of the vulnerability warning to indicate that
  upstream does not believe the issues to be exploitable over the
  network, and
* adds a link to the blog post.

Co-authored-by: Emily <[email protected]>
Signed-off-by: Sumner Evans <[email protected]>
(cherry picked from commit 537d3c4)