CVE-2026-102715EPSS p3.8%
CVE-2026-102715CVE-2026-102715
Description
Any host on the LAN can send two mDNS records and make the responder write past the end of its
transmit packet.
The string table stores each name in a slot rounded up to a multiple of four:
```c
/* addons/mdns/nxd_mdns.c:11436, 11443, 11447 */
memory_len = ((memory_len & 0xFFFFFFFC) + 8) & 0xFFFFFFFF;
...
len = *((USHORT*)(p - 2)); /* slot size, not string length */
if ((len == memory_len) && ... _nx_mdns_name_match(start, memory_ptr, memory_size) ...)
```
The lookup that decides whether an incoming name is already stored compares the rounded slot size,
so names of 12, 13, 14 and 15 characters share one bucket. A second name in the bucket is answered
with the pointer to the first, and the record then carries a string up to three bytes longer than
the length the caller accounted for. `_nx_mdns_packet_rr_add` (nxd_mdns.c:8911) sizes its only
bound check from that stale length, and `_nx_mdns_name_string_encode` writes the real string.
Scoring
| EPSS | 0.15% probability of exploitation · percentile 3.8% · 2026-10-05T12:00:23Z |
| Last modified | 2026-09-29 |