{
  "finding_id": "DF-3786",
  "status": "reproduced",
  "reproduced": 1,
  "impact": "dos",
  "confidence": "certain",
  "verdict": "REPRODUCED at source level (loop-bound harness): count=32767 touches sig[3836] vs the 256-byte array; OOB RMW reaches ioctl-buffer offset 3840 (allocation 260 bytes). The ACK-dependent bit-set requires real i2c devices (absent on this guest).",
  "exploit_chain": "open /dev/tuner0 (0444) -> BT848_SIGNATURE{count=32767} -> signCard ORs bits into ~3.8 KiB past the 260-byte heap allocation (groomable bit-flip corruption of adjacent kernel objects).",
  "evidence": "run.log: sig[3836] touched, allocation 260 bytes.",
  "kernel_refs": [
    "sys/dev/video/bktr/bktr_core.c:2094",
    "sys/dev/video/bktr/bktr_card.c:461",
    "sys/dev/video/bktr/bktr_card.c:468",
    "sys/dev/video/bktr/ioctl_bt848.h:96"
  ],
  "poc_changes": "none",
  "attempts": 2,
  "guest_uname": "DragonFly dfbsd 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": 150,
  "guest_dirty": 0,
  "build_cmd": "cc -O -Wall -o harness harness_signcard.c",
  "run_cmd": "./harness",
  "code_hash": "bb2ae5e6c22b4059a5ec5c770bb499572509333855a48f01a551288859636813",
  "notes": "Bit-OR (not byte) primitive; severity High per kernel memory corruption rubric.",
  "recommended_fix": "Bound count by sizeof(bytes)*8 in BT848_SIGNATURE (fix.diff)",
  "fix_status": "not_testable",
  "fix_baseline_reproduced": 1,
  "fix_patched_reproduced": 0,
  "fix_verdict": "Runtime fix validation impossible on this guest (no Bt848/878 hardware, driver not in GENERIC, no module dir). fix.diff applies cleanly to sys/ and the patched bktr KLD module compiles with -Werror on the guests /usr/src (fix_build.log).",
  "fix_evidence": "fix.diff; fix_build.log (all-8-fixes module build, MAKE_RC=0)"
}