# DF-0316 -- Low

## Verdict: REPRODUCED (source-confirmed)

REAL: wg_output reads *(mtod(m,uint32_t*)) (the AF) without checking m_pkthdr.len>=4, then m_adj(m,4) on a <4-byte packet underflows m_len. Root-only via /dev/bpf DLT_NULL.

## Impact ceiling
none

## Cited refs
- sys/net/wg/if_wg.c:2289

## Fix
Reject packets shorter than sizeof(uint32_t) before reading the AF / m_adj.

## 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.