telnetd in GNU inetutils through 2.7 allows an out-of-bounds write in the LINEMODE SLC (Set Local Characters) suboption handler because add_slc does not check whether the buffer is full.
https://www.openwall.com/lists/oss-security/2026/03/12/4
https://lists.gnu.org/archive/html/bug-inetutils/2026-03/msg00031.html