Allocation of Resources Without Limits or Throttling Affecting io.netty:netty-codec-haproxy package, versions [4.1.0.Final,4.1.136.Final)[4.2.0.Final,4.2.16.Final)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published22 Jul 2026
- disclosed21 Jul 2026
- creditUnknown
Introduced: 21 Jul 2026
NewCVE-2026-55851 (opens in a new tab)How to fix?
Upgrade io.netty:netty-codec-haproxy to version 4.1.136.Final, 4.2.16.Final or higher.
Overview
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the HAProxyMessageDecoder. An attacker can cause unbounded memory allocation by sending a specially crafted PROXY protocol v2 binary prefix with a version byte of 0xFF, which collides with the decoder's sentinel value and leads to continuous accumulation of inbound bytes until memory is exhausted.