NRDAX-T0187 - Oversized Block Response Flood

Memory amplification · Consensus ingest · no bound · active · first seen 2026-07-04

provenance: Reproduced in NullRabbit's attack-reproduction pipeline

mechanism

CometBFT BlocksyncChannel(0x40) oversized BlockResponse (up to 9000 CommitSigs, ~900KB): the Block decode + ValidateBasic at https://github.com/cometbft/cometbft/blob/v0.38.22/blocksync/reactor.go is the wedge. NullRabbit-original measurement.

live exposure

No exposure data. Slashr ↗ has no risk signal mapped to this technique yet — absence of data is not absence of exposure.

instances (1)

chain	primitive	fidelity	origin	reproducer (bundle)	source
cosmos	cometbft_blocksync_flood	lab	NullRabbit Labs	cometbft_blocksync_flood	github.com ↗

related (Memory amplification)

NRDAX-T0023 - Coalesced Packet Buffer Leak active NRDAX-T0025 - Compact Block Size Integer Overflow active NRDAX-T0038 - Count Underflow Header Serving Amplification active NRDAX-T0042 - Crypto Frame Reassembly Buffer Exhaustion active NRDAX-T0046 - Decompression Bomb Resource Exhaustion active NRDAX-T0059 - Duplicate Transport Parameter Memory Leak active NRDAX-T0061 - Duplicate Tx Mempool Index Desync active NRDAX-T0071 - Ethash Verification Memory Exhaustion active

cite

https://nrdax.com/techniques/NRDAX-T0187

plain

NRDAX Registry. Technique NRDAX-T0187.

bibtex

@misc{nrdax_NRDAX_T0187,
  title = {Oversized Block Response Flood (NRDAX-T0187)},
  howpublished = {NRDAX Registry},
  url = {https://nrdax.com/techniques/NRDAX-T0187},
}

json (csl)

{
  "id": "nrdax-NRDAX-T0187",
  "type": "dataset",
  "title": "Oversized Block Response Flood (NRDAX-T0187)",
  "URL": "https://nrdax.com/techniques/NRDAX-T0187",
  "publisher": "NRDAX Registry"
}

badge

[![NRDAX-T0187 in the NRDAX registry](https://nrdax.com/badge/NRDAX-T0187.svg)](https://nrdax.com/techniques/NRDAX-T0187-oversized-block-response-flood)

use from the CLI

Retrieve or cite this technique from a script or the terminal with the NRDAX Python library & CLI.

Retrieve this technique

nrdax get NRDAX-T0187

Cite it (BibTeX)

nrdax cite NRDAX-T0187 --format bibtex

CLI guide → GitHub ↗