# DF-0311 -- Low

## Verdict: REPRODUCED (source-confirmed)

REAL: sopt_to_kbuf's error is overwritten by ip6_setmoptions; a copyin fault leaves a stale/uninit mbuf parsed. ip6_setmoptions's strict m_len checks usually yield EINVAL, masking the garbage. Defense-in-depth.

## Impact ceiling
none

## Cited refs
- sys/netinet6/ip6_output.c:1499

## Fix
Only call ip6_setmoptions when sopt_to_kbuf returned no error.

## Validation
Combined 60-finding fix kernel (findings/poc/_low_merged.patch) built `make -j6 nativekernel KERNCONF=X86_64_GENERIC` => rc=0, 0 errors, -Werror. fix_status=fixed.