Description
`_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.
Every 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.
**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.
**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.
**One-byte residue.** The walker reads a two-byte option header, over-reading one byte.
During 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.
Every 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.
**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.
**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.
**One-byte residue.** The walker reads a two-byte option header, over-reading one byte.
During 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.
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Eclipse Foundation | NetX Duo | unaffected |
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Remediation
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Tracking
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Advisories
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References
History
Tue, 29 Sep 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Tue, 29 Sep 2026 18:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | `_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. Every 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. **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. **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. **One-byte residue.** The walker reads a two-byte option header, over-reading one byte. During 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. | |
| Weaknesses | CWE-125 CWE-1287 CWE-191 CWE-835 |
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| Metrics |
cvssV4_0
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: eclipse
Published:
Updated: 2026-09-29T18:43:50.148Z
Reserved: 2026-09-29T16:15:10.456Z
Link: CVE-2026-102714
Vulnrichment
Updated: 2026-09-29T18:43:00.700Z
NVD
Status : Awaiting Analysis
Published: 2026-09-29T18:17:10.617
Modified: 2026-09-29T19:17:20.460
Link: CVE-2026-102714
Redhat
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OpenCVE Enrichment
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