slightly stricter about what values will be accepted as IP addresses and network
  address ranges (“CIDR blocks”).
  
  In particular, octets within IPv4 addresses are not allowed to have any leading
  `0`s, and IPv4-mapped IPv6 values (e.g. `::ffff:192.168.0.1`) are forbidden.
  These sorts of values can potentially cause security problems when different

 *  Fix: Don't leak connections if web sockets have malformed responses or if `onOpen()` throws.
 *  Fix: Don't retry when request bodies fail due to `FileNotFoundException`.
 *  Fix: Don't crash when URLs have IPv4-mapped IPv6 addresses.
 *  Fix: Don't crash when building `HandshakeCertificates` on Android API 28.
 *  Fix: Permit multipart file names to contain non-ASCII characters.
 *  New: API to get MockWebServer's dispatcher.

- `kubelet` allows pods to use the `net.ipv4.tcp_fin_timeout`, “net.ipv4.tcp_keepalive_intvl”
  and “net.ipv4.tcp_keepalive_probes“ sysctl by default; Pod Security Admission
  allows this sysctl in `v1.29+` versions of the baseline and restricted policies. ([#121240](https://github.com/kubernetes/kubernetes/pull/121240), [@HirazawaUi](https://github.com/HirazawaUi))
- `kubelet` now allows pods to use the `net.ipv4.tcp_keepalive_time` sysctl by default

- IPVS proxier now set net/ipv4/vs/conn_reuse_mode to 0 by default, which will highly improve IPVS proxier performance. ([#71114](https://github.com/kubernetes/kubernetes/pull/71114), [@Lion-Wei](https://github.com/Lion-Wei))

- Kube-proxy doesn't set the sysctl `net.ipv4.conf.all.route_localnet=1` if no IPv4 loopback address is selected by the `nodePortAddresses` configuration parameter. ([#107684](https://github.com/kubernetes/kubernetes/pull/107684), [@aojea](https://github.com/aojea))

  Fixes #135757 ([#135759](https://github.com/kubernetes/kubernetes/pull/135759), [@Abhigyan-Shekhar](https://github.com/Abhigyan-Shekhar)) [SIG API Machinery and CLI]

- Fix a bug that caused to panic the apiserver when trying to allocate a Service with a dynamic ClusterIP and it has been configured with Service CIDRs with a /28 mask for IPv4 and a /124 mask for IPv6 ([#115333](https://github.com/kubernetes/kubernetes/pull/115333), [@aojea](https://github.com/aojea)) [SIG Testing]

### OpenStack

* Fixed a bug in the OpenStack cloud provider where dual stack deployments (IPv4 and IPv6) did not work well when using kubenet as the network plugin. ([#59749](https://github.com/kubernetes/kubernetes/pull/59749), [@zioproto](https://github.com/zioproto))

- Fixed a regression in kube-proxy where it might refuse to start if given
  single-stack IPv6 configuration options on a node that has both IPv4 and
  IPv6 IPs. ([#121008](https://github.com/kubernetes/kubernetes/pull/121008), [@danwinship](https://github.com/danwinship)) [SIG Network]

- Fixed an issue in the Windows kube-proxy (winkernel) where IPv4 and IPv6 Service load balancers could be incorrectly shared, causing broken dual-stack Service behavior. The kube-proxy now tracks load balancers per IP family, enabling correct support for PreferDualStack and RequireDualStack Services on Windows nodes....