---
id: CVE-2026-67298
title: >-
  FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the
  server-side RAIL channel handler (rail_server_handle_messages() in
  channels/rail/server/rail_main.c)
summary: >-
  FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the
  server-side RAIL channel handler (rail_server_handle_messages() in
  channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code
  subtracts RAIL_PD…
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'
cwe:
  - CWE-191
published: '2026-08-01'
updated: '2026-08-01'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67298'
references:
  - url: >-
      https://github.com/FreeRDP/FreeRDP/commit/46848765f2a1134f8652f8760eefb5e85d64a9b8
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/FreeRDP/FreeRDP/commit/5370fb26fbf034ecd11d3026b6ad639b5fff493f
    label: disclosure@vulncheck.com
  - url: 'https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-qmvw-52ph-q5pv'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-via-rail-orderlength-underflow
    label: disclosure@vulncheck.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67298.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-67298'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2510041'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-67298'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67298'
  - url: 'https://access.redhat.com/errata/RHSA-2026:61378'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68707'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68706'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
ingestedAt: '2026-08-02T05:17:49.662Z'
epss: 0.0067
epssPercentile: 0.49884
vendor: Red Hat
product: Red Hat Enterprise Linux AppStream (v. 10)
affected:
  - enterprise_linux 6
  - enterprise_linux 7
  - enterprise_linux_appstream_v_10
  - enterprise_linux_codeready_linux_builder_v_10
patched:
  - enterprise_linux_appstream_v_10
  - enterprise_linux_codeready_linux_builder_v_10
scores:
  nvd: 7.5
  vendor: 7.1
---

## Overview

FreeRDP versions 3.28.0 and earlier contain a heap buffer overflow in the server-side RAIL channel handler (rail_server_handle_messages() in channels/rail/server/rail_main.c). When processing a RAIL PDU header, the code subtracts RAIL_PDU_HEADER_LENGTH from the peer-controlled orderLength field without first verifying orderLength is at least the header length. For orderLength values 0..3 this causes an unsigned integer underflow to a very large size, which bypasses the Stream_EnsureRemainingCapacity() capacity check (due to pointer arithmetic wraparound) and is then passed to WTSVirtualChannelRead(), resulting in an out-of-bounds heap write. A malicious or compromised RDP client can exploit this to corrupt the heap and crash the server. Fixed in FreeRDP 3.29.0.

## Remediation

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

## Vendor advisories

- **RHSA-2026:61378** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:61378)
- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 6 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67298.json)
- **RHSA-2026:68707** · Red Hat · fixed in: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68707)
- **RHSA-2026:68706** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68706)