In the /HNAP1/SetQoSSettings message, the uplink parameter is vulnerable, and the vulnerability affects D-Link DIR-822 Rev.B 202KRb06 and DIR-822 Rev.C 3.10B06 devices. In the SetQoSSettings.php source code, the uplink parameter is saved in the /bwc/entry:1/bandwidth and /bwc/entry:2/bandwidth internal configuration memory without any regex checking. And in the bwc_tc_spq_start, bwc_tc_wfq_start, and bwc_tc_adb_start functions of the bwcsvcs.php source code, the data in /bwc/entry:1/bandwidth and /bwc/entry:2/bandwidth is used with the tc command without any regex checking. A vulnerable /HNAP1/SetQoSSettings XML message could have shell metacharacters in the uplink element such as the `telnetd` string.
Use CWE-78, D-Link vendor hub and Dir-822 Firmware product page to widen CVE-2018-19989 into its surrounding weakness, vendor, and product context.
Compare it with CVE-2019-6258, CVE-2018-19990 and CVE-2018-19987 for nearby disclosures in the same product family.