{"id":"CVE-2026-102714","title":"`_nx_icmpv6_validate_options()` scans the option area with `while (length > 2)` (`common/src/nx_icmpv6_validate_options.c:79`)","summary":"`_nx_icmpv6_validate_options()` scans the option area with `while (length > 2)` (`common/src/nx_icmpv6_validate_options.c:79`). An area whose size leaves a one- or two-byte residue exits the loop with that tail unexamined; the residue is…","severity":"high","cvss":7.1,"cvssVector":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","cwe":["CWE-125","CWE-191","CWE-835","CWE-1287"],"vendor":"Eclipse Foundation","product":"NetX Duo","affected":["netx_duo <= 6.5.1.202602"],"published":"2026-09-29","updated":"2026-09-29","sourceUpdated":"2026-09-29T18:17:10.617","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-102714","references":[{"url":"https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-39p4-p83c-58hr","label":"emo@eclipse.org"}],"tags":["nvd","cve.org"],"cvssSource":"cna","ingestedAt":"2026-09-29T18:42:35.813Z","slug":"CVE-2026-102714","body":"## Overview\n\n`_nx_icmpv6_validate_options()` scans the option area with `while (length > 2)` (`common/src/nx_icmpv6_validate_options.c:79`). An area whose size leaves a one- or two-byte residue exits the loop with that tail unexamined; the residue is not negative, so the function returns `NX_SUCCESS`. Its zero-length rejection never sees those bytes.\n\n\n\nEvery consumer then re-walks the same area, reading a two-byte option header at the residue and subtracting `nx_icmpv6_option_length << 3` with no zero check and no remaining-length check. Three outcomes follow, selected by bytes the attacker controls.\n\n\n\n**Zero length byte.** The walker subtracts zero and advances zero. All four handlers loop forever — `_nx_icmpv6_process_ra` (`nx_icmpv6_process_ra.c:245, :528`), `_nx_icmpv6_process_ns` (`:251, :329`), `_nx_icmpv6_process_na` (`:147, :156`) and `_nx_icmpv6_process_redirect` (`:247, :350`). The walk runs in the IP thread, which is the highest-priority thread and does not yield inside the loop, so the system stops until a watchdog reset and the frame can be replayed after each one.\n\n\n\n**Non-zero length byte on a short residue.** The three unsigned counters underflow — `2 - 8` becomes `0xFFFFFFFA` — and the walk continues past the packet buffer, reading until it faults or meets a zero length byte and freezes. The Router Advertisement counter is signed and exits cleanly in this case.\n\n\n\n**One-byte residue.** The walker reads a two-byte option header, over-reading one byte.\n\n\n\nDuring a runaway walk, stray bytes parsing as a link-layer address option are copied into the neighbor cache (`nx_icmpv6_process_ns.c:280, :293`) and subsequently used as the destination MAC for frames to that neighbour, placing off-packet memory on the link. Confirmed by inspection, not reproduced.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}