NRDAX-T0386 - Priority-Field Parse-Exception Leak

memory_amp · active · first seen 2026-07-13

provenance: Reproduced in NullRabbit's attack-reproduction pipeline

mechanism

The HTTP/2 priority parser (RFC 9218 urgency field) throws an unhandled IllegalArgumentException when given an out-of-range value (e.g. u=99), and the request-handling code path lacks a catch/cleanup for this failure, leaving the half-processed request's state permanently retained. An attacker floods the server with malformed PRIORITY_UPDATE frames or priority headers, each triggering the same uncaught-exception path, causing unbounded cumulative memory retention across requests. Effect: gradual heap growth culminating in OutOfMemoryError / DoS. The fix-class is 'catch parser exceptions and ensure per-request cleanup/dispatch on all error paths', distinguishing it from stream-count or flow-control exhaustion techniques.

instances (1)

chain	primitive	fidelity	origin	reproducer (bundle)	source
http2	http2_malformed_priority_leak_flood	lab	reverse-engineered-cve	http2_malformed_priority_leak_flood	-

related (memory_amp)

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-T0386

plain

NRDAX Registry. Technique NRDAX-T0386.

bibtex

@misc{nrdax_NRDAX_T0386,
  title = {Priority-Field Parse-Exception Leak (NRDAX-T0386)},
  howpublished = {NRDAX Registry},
  url = {https://nrdax.com/techniques/NRDAX-T0386},
}

json (csl)

{
  "id": "nrdax-NRDAX-T0386",
  "type": "dataset",
  "title": "Priority-Field Parse-Exception Leak (NRDAX-T0386)",
  "URL": "https://nrdax.com/techniques/NRDAX-T0386",
  "publisher": "NRDAX Registry"
}