{
 "finding_id": "DF-3411",
 "status": "not_reproduced",
 "reproduced": 0,
 "poc_path": "findings/poc/DF-3411",
 "artifact_dir": "findings/poc/DF-3411",
 "build_cmd": "cc -O -o <prog> <prog>.c  (on the guest)",
 "run_cmd": "20 (root)",
 "code_hash": "3a75e80ae23dee45f0ec16d75f548117db8c847508d631ac92860299077da5be",
 "build_log": "(inline)",
 "run_log": "VERDICT.md",
 "impact": "none",
 "confidence": "likely",
 "verdict": "funsetown (kern_descrip.c:1239-1273) drops sigio_token BEFORE the list removal/crfree/kfree while pgsigio (kern_sig.c:2639) derefs the sigio with no token: tunifstarts pgsigio(sc->tun_sigio) racing a concurrent FIOSETOWN is a genuine use-after-free window. Stress attempted live (FIOSETOWN hammer + continuous tun0 traffic driving tunifstart): ~55s combined, no crash; window is a handful of instructions. Mechanism line-confirmed.",
 "exploit_chain": "",
 "evidence": "VERDICT.md run log: FIOSETOWN storm + ping/UDP traffic through tun0, rc=124 (alive, no crash)",
 "kernel_refs": [
  "sys/net/tun/if_tun.c:533-536",
  "sys/kern/kern_descrip.c:1239-1273",
  "sys/kern/kern_sig.c:2639-2663"
 ],
 "poc_changes": "",
 "attempts": 3,
 "guest_uname": "DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC x86_64",
 "runtime_sec": 60,
 "guest_dirty": 0,
 "runner": "df-bsd-reviewer",
 "notes": "",
 "recommended_fix": "",
 "fix_status": "not_testable",
 "fix_verdict": "Fix: hold sigio_token across the pgsigio body (or make tun read sc->tun_sigio under the token); needs fault injection to A/B.",
 "fix_baseline_reproduced": null,
 "fix_patched_reproduced": null
}