doc: clarify v4.2.3 notable items

* Include reference to CVE-2015-8027
* Fix "socket may no longer have a socket" reference
* Expand on non-existent parser causing the error
* Soften language for CVE-2015-3193 as impact may not be as great as
  expected
* Clarify that CVE-2015-3194 affects TLS servers using _client
  certificate authentication_
* Include reference to CVE-2015-6764
* Remove links to nodejs/node-private in commits list

PR-URL: #4155
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

CHANGELOG.md

@@ -6,12 +6,12 @@ Security Update
 
 ### Notable changes
 
-* **http**: Fix a bug where an HTTP socket may no longer have a socket but a pipelined request triggers a pause or resume, a potential denial-of-service vector. (Fedor Indutny)
+* **http**: Fix CVE-2015-8027, a bug whereby an HTTP socket may no longer have a parser associated with it but a pipelined request attempts to trigger a pause or resume on the non-existent parser, a potential denial-of-service vulnerability. (Fedor Indutny)
 * **openssl**: Upgrade to 1.0.2e, containing fixes for:
-  - CVE-2015-3193 "BN_mod_exp may produce incorrect results on x86_64", an attack is considered feasible against a Node.js TLS server using DHE key exchange. Details are available at <http://openssl.org/news/secadv/20151203.txt>.
-  - CVE-2015-3194 "Certificate verify crash with missing PSS parameter", a potential denial-of-service vector for Node.js TLS servers; TLS clients are also impacted. Details are available at <http://openssl.org/news/secadv/20151203.txt>.
+  - CVE-2015-3193 "BN_mod_exp may produce incorrect results on x86_64", an attack may be possible against a Node.js TLS server using DHE key exchange. Details are available at <http://openssl.org/news/secadv/20151203.txt>.
+  - CVE-2015-3194 "Certificate verify crash with missing PSS parameter", a potential denial-of-service vector for Node.js TLS servers using client certificate authentication; TLS clients are also impacted. Details are available at <http://openssl.org/news/secadv/20151203.txt>.
   (Shigeki Ohtsu) [#4134](https://github.com/nodejs/node/pull/4134)
-* **v8**: Backport fixes for a bug in `JSON.stringify()` that can result in out-of-bounds reads for arrays. (Ben Noordhuis)
+* **v8**: Backport fix for CVE-2015-6764, a bug in `JSON.stringify()` that can result in out-of-bounds reads for arrays. (Ben Noordhuis)
 
 ### Known issues
 
@@ -23,9 +23,9 @@ Security Update
 ### Commits
 
 * [[`49bbd563be`](https://github.com/nodejs/node/commit/49bbd563be)] - **deps**: upgrade openssl sources to 1.0.2e (Shigeki Ohtsu) [#4134](https://github.com/nodejs/node/pull/4134)
-* [[`9a063fd492`](https://github.com/nodejs/node/commit/9a063fd492)] - **deps**: backport a7e50a5 from upstream v8 (Ben Noordhuis) [nodejs/node-private#8](https://github.com/nodejs/node-private/pull/8)
-* [[`07233206e9`](https://github.com/nodejs/node/commit/07233206e9)] - **deps**: backport 6df9a1d from upstream v8 (Ben Noordhuis) [nodejs/node-private#8](https://github.com/nodejs/node-private/pull/8)
-* [[`1c8e6de78e`](https://github.com/nodejs/node/commit/1c8e6de78e)] - **http**: fix pipeline regression (Fedor Indutny) [nodejs/node-private#5](https://github.com/nodejs/node-private/pull/5)
+* [[`9a063fd492`](https://github.com/nodejs/node/commit/9a063fd492)] - **deps**: backport a7e50a5 from upstream v8 (Ben Noordhuis)
+* [[`07233206e9`](https://github.com/nodejs/node/commit/07233206e9)] - **deps**: backport 6df9a1d from upstream v8 (Ben Noordhuis)
+* [[`1c8e6de78e`](https://github.com/nodejs/node/commit/1c8e6de78e)] - **http**: fix pipeline regression (Fedor Indutny)
 
 ## 2015-11-03, Version 4.2.2 'Argon' (LTS), @jasnell