{"id":5072,"date":"2026-09-04T18:46:59","date_gmt":"2026-09-04T10:46:59","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-5857"},"modified":"2026-09-04T18:46:59","modified_gmt":"2026-09-04T10:46:59","slug":"cve-2026-5857","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-5857","title":{"rendered":"CVE-2026-5857 [HIGH] &#8211; Contiki-NG&#8217;s MQTT client parse_publish_vhdr() in os\/net\/app-layer\/mqtt\/mqtt.c sets topic_l"},"content":{"rendered":"<p>Contiki-NG&#8217;s MQTT client parse_publish_vhdr() in os\/net\/app-layer\/mqtt\/mqtt.c sets topic_len_received=1 before checking topic_len against the 64-byte limit, so an over-length topic returns early but leaves the flag set. On the next TCP segment, tcp_input() re-invokes the parser with topic_received==0, and the persisted topic_len_received==1 skips the length-reading block containing the guard, falling through directly to a memcpy() that uses the unvalidated 16-bit topic_len as the copy length. The 65-byte topic[] destination overruns into adjacent struct fields including the payload_chunk pointer, which subsequent MQTT code dereferences, giving a compromised or attacker-controlled broker an arbitrary-pointer-write primitive. Contiki-NG&#8217;s MQTT implementation has no TLS support so the connection is plaintext. Impact ranges from information disclosure and denial of service to remote code execution on embedded targets without memory protection.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Contiki-NG&#8217;s MQTT client parse_publish_vhdr() in os\/net\/app-layer\/mqtt\/mqtt.c sets topic_len_received=1 before checking topic_len against the 64-byte limit, so an over-length topic returns early but l<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-5072","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/5072","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5072"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5072"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5072"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}