PT-2026-65342 · Maven · Io.Netty:Netty-Codec-Dns

Publicado

2026-07-24

·

Atualizado

2026-07-24

CVSS v3.1

5.3

Média

VetorAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Summary

A memory leak can be caused in Netty's DNS codec by sending malicious DNS packets containing invalid domain names. Because the leak occurs incrementally per packet, sustained malicious requests will cause a gradual Denial of Service.

Details

Inside io.netty.handler.codec.dns.AbstractDnsRecord, the parsed domain name string is passed to IDN.toASCII(name). If the domain name contains characters that violate IDNA rules, IDN.toASCII throws an IllegalArgumentException.
Because this exception occurs inside the constructor before the DnsRecord instance can assign the buffer to its content field for later release, the ByteBuf whose reference count was incremented (or newly allocated) is never released, resulting in a direct memory leak.
There are several places where variants of this leak happen:
  • io.netty.handler.codec.dns.DefaultDnsRecordDecoder#decodeRecord(java.lang.String, io.netty.handler.codec.dns.DnsRecordType, int, long, io.netty.buffer.ByteBuf, int, int) invokes in.retainedDuplicate() or creates a new buffer out when constructing DefaultDnsRawRecord
  • io.netty.handler.codec.dns.DnsCodecUtil#decompressDomainName allocates a new ByteBuf and passes it to encodeDomainName(). If the decompressed domain name contains a null byte (0), encodeDomainName() throws an IllegalArgumentException, leaking the newly allocated buffer.

Impact

Resource Exhaustion. Any application utilizing Netty's DnsRecordDecoder (such as DnsNameResolver or custom DNS servers) is vulnerable.

Correção

Missing Release of Resource after Effective Lifetime

Encontrou algum problema na descrição? Tem algo a acrescentar? Fique à vontade para nos escrever 👾
dbugs@ptsecurity.com

Enumeração de Fraquezas

CWE-772

Identificadores relacionados

GHSA-MFG7-5GFP-C4W3

Produtos afetados

Io.Netty:Netty-Codec-Dns