Same problem here - updated busybox (it is noted now, that I won't do that again..) and stubby stopped working. Took me half a day to finally fix that part (by setting tls_ca_file
to the certificates bundle file instead of the directory) to get online again. Also had issues with openvpn and therefore with vpn routing (VPN-PBR).
so far I tried: I stopped all VPN related things to get this out of the way. I tried the marked solution - which somehow removed the stubby package (?). I reinstalled adblock, libustream-mbedtls (and stubby).
Current status: stubby needs an extra restart after a reboot and I still get errors in the adblock log. But most of the sources work. I am not 100% if those errors where there before the update or if this is just a temporary problem of the selected source. Would be glad if someone could verify this.
Sun Aug 23 09:44:29 2020 user.info adblock-4.0.6[6403]: download of 'reg_de' failed, url: https://easylist-downloads.adblockplus.org/easylistgermany+easylist.txt, rule: BEGIN{FS="[|^]"}/^\|\|([[:alnum:]_-]{1,63}\.)+[[:alpha:]]+\^(\$third-party)?$/{print tolower($3)}, categories: -, rc: 4, log: Downloading 'https://easylist-downloads.adblockplus.org/easylistgermany+easylist.txt' Failed to send request: Operation not permitted
Sun Aug 23 09:44:30 2020 user.info adblock-4.0.6[6403]: download of 'reg_cn' failed, url: https://easylist-downloads.adblockplus.org/easylistchina+easylist.txt, rule: BEGIN{FS="[|^]"}/^\|\|([[:alnum:]_-]{1,63}\.)+[[:alpha:]]+\^(\$third-party)?$/{print tolower($3)}, categories: -, rc: 4, log: Downloading 'https://easylist-downloads.adblockplus.org/easylistchina+easylist.txt' Failed to send request: Operation not permitted
Sun Aug 23 09:45:54 2020 user.info adblock-4.0.6[6403]: blocklist with overall 330150 blocked domains loaded successfully (TP-Link Archer C2600, OpenWrt 19.07.3 r11063-85e04e9f46)
my config:
Status / Version enabled / 4.0.6
Blocked Domains 330.150
Active Sources adaway, adguard, andryou, anti_ad, anudeep, bitcoin, disconnect, malwaredomains, malwarelist, notracking, openphish, phishing_army, reg_cn, reg_de, smarttv, spam404, stopforumspam, utcapitole, wally3k, whocares, winhelp, winspy, youtube, yoyo
DNS Backend dnsmasq, /tmp/dnsmasq.d
Run Utils /bin/uclient-fetch, /usr/bin/awk
Run Interfaces trigger: wan, report: br-lan
Run Directories base: /tmp, backup: /tmp, report: /tmp, jail: /tmp
Run Flags backup: 1, reset: 0, flush: 0, force: 1, search: 0, report: 1, mail: 0, jail: 0
Last Run start, 2m 59s, 480/287/279, 23.08.2020 09:45:53