The following updates has been released for CentOS Linux 6 and 7:

CESA-2017:2831 Critical CentOS 6 firefox Security Update
CESA-2017:2831 Critical CentOS 7 firefox Security Update
CESA-2017:2832 Important CentOS 6 nss Security Update
CESA-2017:2832 Important CentOS 7 nss Security Update

CESA-2017:2831 Critical CentOS 6 firefox Security Update

CentOS Errata and Security Advisory 2017:2831 Critical

Upstream details at : https://access.redhat.com/errata/RHSA-2017:2831

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

i386:
212c25531aad7cec6beca513117f0670480cd67b006eac0daeb242bf8fc73805 firefox-52.4.0-1.el6.centos.i686.rpm

x86_64:
212c25531aad7cec6beca513117f0670480cd67b006eac0daeb242bf8fc73805 firefox-52.4.0-1.el6.centos.i686.rpm
052aac090689b63de266e303cad69eb2a39a39c21e06a813562390904315a6e5 firefox-52.4.0-1.el6.centos.x86_64.rpm

Source:
f990185e5803de42e5351d31c276001677afaa4120bcb9b3f6d11190267805e1 firefox-52.4.0-1.el6.centos.src.rpm

CESA-2017:2831 Critical CentOS 7 firefox Security Update

CentOS Errata and Security Advisory 2017:2831 Critical

Upstream details at : https://access.redhat.com/errata/RHSA-2017:2831

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

x86_64:
c50ba8648e3b2c32b65ed9d0a6718e34a19fb2180cd113f473a6b6eb5e87900b firefox-52.4.0-1.el7.centos.i686.rpm
29bdc5ec8e8155854d7ac2605fdacb15ad40bcb8728825c4b1531b0e5da3df67 firefox-52.4.0-1.el7.centos.x86_64.rpm

Source:
fba2da970bd16d5519beed16bc239ee8dcc3c4298217af7a2ba390c36e69a01a firefox-52.4.0-1.el7.centos.src.rpm

CESA-2017:2832 Important CentOS 6 nss Security Update

CentOS Errata and Security Advisory 2017:2832 Important

Upstream details at : https://access.redhat.com/errata/RHSA-2017:2832

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

i386:
56099ae34645fa89d00010fe614df83a79a1925be3830dcbb67e9b00b38894a9 nss-3.28.4-4.el6_9.i686.rpm
025a8491a6c1e927bc9662eb305f6482240491f389e90ed0e7ab835344d95c96 nss-devel-3.28.4-4.el6_9.i686.rpm
0f3a6773e86d60fcb4bcda3aaa1fba7428440bdd81aa3bd926faebf3ff72dca9 nss-pkcs11-devel-3.28.4-4.el6_9.i686.rpm
3dd0702db2d70534d11377ae3f8624f7775671d3118a1b4780b5ff9bcbb7e91c nss-sysinit-3.28.4-4.el6_9.i686.rpm
2f80dcab9ee5602fb3764cbbceef4d14c4e720d3a680f930c00db47a1871c2b6 nss-tools-3.28.4-4.el6_9.i686.rpm

x86_64:
56099ae34645fa89d00010fe614df83a79a1925be3830dcbb67e9b00b38894a9 nss-3.28.4-4.el6_9.i686.rpm
9443be70c900ba4987de5f794275c757aafadfe2f6f0445cd296857c371caa0b nss-3.28.4-4.el6_9.x86_64.rpm
025a8491a6c1e927bc9662eb305f6482240491f389e90ed0e7ab835344d95c96 nss-devel-3.28.4-4.el6_9.i686.rpm
615d1ebd1932ec30b3f94a50140646848036aa273d0d80593bc23817dd40b252 nss-devel-3.28.4-4.el6_9.x86_64.rpm
0f3a6773e86d60fcb4bcda3aaa1fba7428440bdd81aa3bd926faebf3ff72dca9 nss-pkcs11-devel-3.28.4-4.el6_9.i686.rpm
4ed35c5d70b8699c1e4cfb545718a7e06c009b3acfbf7282bc468a84dd62b6a8 nss-pkcs11-devel-3.28.4-4.el6_9.x86_64.rpm
3ba7c3ccb98ffb6545175105f6023c11fdb59c7e64a03e93662ea54e8e5b4bfa nss-sysinit-3.28.4-4.el6_9.x86_64.rpm
ad77a286969f96d8edf181d2489ec6dff094a91ceb7fe3da27b75e5492340c80 nss-tools-3.28.4-4.el6_9.x86_64.rpm

Source:
2679e522de097abe0fd65de3ab24fdf9d1e5b5ec71f677b601dafc9d45b9b53e nss-3.28.4-4.el6_9.src.rpm

CESA-2017:2832 Important CentOS 7 nss Security Update

CentOS Errata and Security Advisory 2017:2832 Important

Upstream details at : https://access.redhat.com/errata/RHSA-2017:2832

The following updated files have been uploaded and are currently
syncing to the mirrors: ( sha256sum Filename )

x86_64:
5b9f01457f88d0b6b4f442b2f7c4d5318962b9a3321ee79fee9d9f541513d439 nss-3.28.4-12.el7_4.i686.rpm
8443f61e40876db42ec1e5ea0fcb45cb2d0cc2647752a5e2ae03939d3ff08628 nss-3.28.4-12.el7_4.x86_64.rpm
3431721d1a3876799351c45b6923d123c69847ccdea17de5d82151412c979c33 nss-devel-3.28.4-12.el7_4.i686.rpm
1116f9a4e85302f4b85fc4511153e2623841c22b6a733d9b061331be46c5022d nss-devel-3.28.4-12.el7_4.x86_64.rpm
c16e3a00b15df077d56996572a16482593795c0e798a3e879af186a7987ea93f nss-pkcs11-devel-3.28.4-12.el7_4.i686.rpm
a8998872a428c177201f6db49c3f24472eb78729ebb1a15731440739a2155da1 nss-pkcs11-devel-3.28.4-12.el7_4.x86_64.rpm
de14017234abf879caf5843aacc732719dbde7e033d824b57224bd34f55b73ae nss-sysinit-3.28.4-12.el7_4.x86_64.rpm
66b4b4bb2a679ddfe0471a33774aa1c0f17388a04b319056cb9dd3ed5060f230 nss-tools-3.28.4-12.el7_4.x86_64.rpm

Source:
6725abae2df7fbc35d33545095c51e4e3bfc559fc323b73bf07d19f06e062bee nss-3.28.4-12.el7_4.src.rpm