1. What is the procedure for patch updates for LibreOffice?
Basically, uninstall the old version of LibO, install the new version of
LibO. As a general rule, copying the /config/LibO/old-version/user
directory to /config/LibO/new-version/user migrates customizations. The
big exception is installed extensions. Those will have to be manually
done. (If LibO is compiled in-house, necessary extensions can be
included in that build process.)
The specific process depends upon the platform that is used.
Note: neither Android nor iOS on the iPhone, iPod, or iPad are currently
supported. You'll have to write a lot of code, to have a usable version
of LibO on those platforms.)
2. How will I get the information that any vulnerability has identified in LibreOffice?
https://www.libreoffice.org/about-us/security/advisories/ is a list of
fixed, known vulnerabilities.
Coverty scan results are posted to libreoffice@lists.freedesktop.org
every month.
http://nabble.documentfoundation.org/New-Defects-reported-by-Coverity-Scan-for-LibreOffice-td4191140.html
is a fairly typical report.
If you're wanting announcements, such as that described at
https://www.helpnetsecurity.com/2016/06/30/libreoffice-flaw-godsend-hackers/,
a Google Alert is your best bet. (That specific flaw was fixed in LibO
5.1.4/5.2.0.)
3. How will I get the information about new updates available for LibreOffice?
announce@documentfoundation.org: Mailing list for news and press
releases by The Document Foundation.
Subscription: announce+subscribe@documentfoundation.org
Digest subscription: announce+subscribe-digest@documentfoundation.org
Archives: http://listarchives.documentfoundation.org/www/announce/
Mail-Archive.com:
http://www.mail-archive.com/announce@documentfoundation.org/
GMANE: http://dir.gmane.org/gmane.comp.documentfoundation.announce
That is a low traffic mailing list. Roughly half the messages are about
new releases of either the program, or documentation.
4. Who will support us in case if any outbreaks happens due to any vulnerabilities?
https://www.libreoffice.org/get-help/professional-support/ is a list of
vendors of Tier 1 through Tier 3 support, that have undergone TDF
certification.
LibreOffice, as a project, and _The Document Foundation_, as an
organization, provide Tier 0 support.
5. What is timeline to provide the fix to any vulnerability?
That depends on how severe the vulnerability is, and how much other code
is affected by rewritten the vulnerable code.