---
id: CVE-2026-56786
title: >-
  RTKLIB 2.4.3 - Out-of-bounds Write in decode_type1033 via Crafted RTCM3
  Message
summary: >-
  RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in
  decode_type1033 function that fails to clamp length counters to destination
  buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor
  fields. An atta…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-787
vendor: tomojitakasu
product: RTKLIB
affected:
  - RTKLIB <= 2.4.3
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-06-25T18:41:31.254908Z'
exploitAvailable: true
published: '2026-06-25'
updated: '2026-11-08'
sourceUpdated: '2026-11-08T14:06:25.525Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-56786'
references:
  - url: 'https://github.com/tomojitakasu/RTKLIB/issues/799'
    label: Researcher Disclosure
  - url: >-
      https://www.vulncheck.com/advisories/rtklib-out-of-bounds-write-in-decode-type1033-via-crafted-rtcm3-message
tags:
  - cve.org
  - exploit-available
epss: 0.00711
epssPercentile: 0.53817
ingestedAt: '2026-11-08T14:51:22.332Z'
---

## Overview

RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can craft a valid CRC-bearing type-1033 message to corrupt adjacent rtcm_t object members, potentially achieving arbitrary code execution or denial of service.

## Affected

- `RTKLIB <= 2.4.3`

## Remediation

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