---
id: CVE-2026-59803
title: rpcx - Denial of Service via Gzip Decompression Bomb in Wire Protocol
summary: >-
  rpcx through 1.9.3, fixed in commit 047aec1, contains a denial-of-service
  vulnerability in protocol.Message.Decode (protocol/message.go). When a message
  has the compression flag set, the payload is gzip-decompressed via util.Unzip
  with n…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-409
vendor: smallnest
product: rpcx
affected:
  - rpcx <= 1.9.3
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-07-09T13:29:48.308645Z'
exploitAvailable: true
published: '2026-07-08'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:07:23.595Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-59803'
references:
  - url: 'https://github.com/smallnest/rpcx/issues/942'
    label: Researcher Disclosure
  - url: 'https://github.com/smallnest/rpcx/pull/943'
    label: Fix PR
  - url: >-
      https://github.com/smallnest/rpcx/commit/047aec18efa7d037105e2b72c36dd2ae05e1acc6
    label: Fix Commit
  - url: >-
      https://www.vulncheck.com/advisories/rpcx-denial-of-service-via-gzip-decompression-bomb-in-wire-protocol
tags:
  - cve.org
  - exploit-available
epss: 0.00742
epssPercentile: 0.54936
ingestedAt: '2026-11-08T14:51:22.279Z'
---

## Overview

rpcx through 1.9.3, fixed in commit 047aec1, contains a denial-of-service vulnerability in protocol.Message.Decode (protocol/message.go). When a message has the compression flag set, the payload is gzip-decompressed via util.Unzip with no limit on the decompressed output size. The only built-in size guard, protocol.MaxMessageLength, is checked against the compressed on-the-wire frame length, not the decompressed size, so it provides no protection. Because decoding (and decompression) occurs in readRequest before authentication, a single unauthenticated connection can send a small (under 2 MB) gzip-compressed message that expands to gigabytes of heap allocation, leading to out-of-memory conditions and service unavailability.

## Affected

- `rpcx <= 1.9.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.