{"id":"CVE-2026-102715","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-102715","generatedAt":"2026-10-28T00:59:37.700Z","title":"Two PTR records are enough, both ordinary mDNS responses to a `_http._tcp` query, with owner names whose lengths fall in the same bucket: ``` ==87491==ERROR: AddressSanitizer: heap-buffer-overflow WRITE of size 1 at 0x611000000124 thread T5 #0…","description":"Any host on the LAN can send two mDNS records and make the responder write past the end of its\n\n\n\ntransmit packet.\n\n\n\nThe string table stores each name in a slot rounded up to a multiple of four:\n\n\n\n```c\n\n\n\n/* addons/mdns/nxd_mdns.c:11436, 11443, 11447 */\n\n\n\nmemory_len = ((memory_len & 0xFFFFFFFC) + 8) & 0xFFFFFFFF;\n\n\n\n...\n\n\n\nlen = *((USHORT*)(p - 2));           /* slot size, not string length */\n\n\n\nif ((len == memory_len) && ... _nx_mdns_name_match(start, memory_ptr, memory_size) ...)\n\n\n\n```\n\n\n\nThe lookup that decides whether an incoming name is already stored compares the rounded slot size,\n\n\n\nso names of 12, 13, 14 and 15 characters share one bucket. A second name in the bucket is answered\n\n\n\nwith the pointer to the first, and the record then carries a string up to three bytes longer than\n\n\n\nthe length the caller accounted for. `_nx_mdns_packet_rr_add` (nxd_mdns.c:8911) sizes its only\n\n\n\nbound check from that stale length, and `_nx_mdns_name_string_encode` writes the real string.\n\n\n\nTwo PTR records are enough, both ordinary mDNS responses to a `_http._tcp` query, with owner names\n\n\n\nwhose lengths fall in the same bucket:\n\n\n\n```\n\n\n\n==87491==ERROR: AddressSanitizer: heap-buffer-overflow\n\n\n\nWRITE of size 1 at 0x611000000124 thread T5\n\n    #0 _nx_mdns_name_string_encode  addons/mdns/nxd_mdns.c:13096\n    #1 _nx_mdns_packet_rr_add       addons/mdns/nxd_mdns.c:8911\n\n\n0x611000000124 is 0 bytes to the right of 228-byte region\n\n\n\n```\n\n\n\nThe overflow is one to three bytes of attacker-influenced name data past `nx_packet_data_end`. In a\n\n\n\nnormal pool that lands in the next packet in the same pool rather than in a redzone, so the visible\n\n\n\neffect is a corrupted neighbouring packet or a corrupted pool free list rather than a clean crash.\n\n\n\nCompare the slot size against the stored string length before declaring a match, or keep the\n\n\n\nstring length in the slot header and return it to the caller so the encoder and the bound check\n\n\n\nagree.","published":"2026-09-29T18:17:11.000Z","lastModified":"2026-09-29T19:17:21.000Z","status":"Awaiting Analysis","sourceIdentifier":"emo@eclipse.org","cvss":{"version":"4.0","score":7.1,"severity":"HIGH","vector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-787"],"affected":[],"epss":{"score":0.00153,"percentile":0.04388,"date":"2026-10-26","history":[{"date":"2026-09-30","score":0.00153,"percentile":0.03786}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.15%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-09-29T18:17:11.000Z","detail":{"score":"7.1","severity":"HIGH","publishedAt":"2026-09-29T18:17:10.780Z"},"summary":"New CVE, high severity (CVSS 7.1)."}],"references":[{"url":"https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-2gf7-5224-5vrj","source":"emo@eclipse.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-102715","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}