---
id: CVE-2026-50161
title: >-
  libre is a generic library for real-time communications with asynchronous
  input and output support
summary: >-
  libre is a generic library for real-time communications with asynchronous
  input and output support. Prior to 4.8.1, the websock_decode() function in
  src/websock/websock.c contains an integer overflow when validating a masked
  WebSocket fr…
severity: critical
cwe:
  - CWE-190
  - CWE-787
published: '2026-08-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T20:09:01.757'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-50161'
references:
  - url: >-
      https://github.com/baresip/re/commit/718b92615c7963670d26c1a2b246968b58d782e8
    label: security-advisories@github.com
  - url: 'https://github.com/baresip/re/pull/1584'
    label: security-advisories@github.com
  - url: 'https://github.com/baresip/re/releases/tag/v4.8.1'
    label: security-advisories@github.com
  - url: 'https://github.com/baresip/re/security/advisories/GHSA-hvxv-v2gp-v93h'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-50161.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-50161'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-50161'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00524
epssPercentile: 0.42008
ingestedAt: '2026-09-18T20:51:25.633Z'
vendor: Red Hat
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: vendor
---

## Overview

libre is a generic library for real-time communications with asynchronous input and output support. Prior to 4.8.1, the websock_decode() function in src/websock/websock.c contains an integer overflow when validating a masked WebSocket frame that uses the 64-bit extended length encoding. The expression 4 + hdr->len can wrap when hdr->len is close to UINT64_MAX, causing the mbuf_get_left() bounds check to pass. The subsequent XOR unmasking loop then writes beyond the heap buffer. Applications using websock_accept() or websock_accept_proto() to implement a WebSocket server are affected, and exploitation can cause attacker-controlled heap corruption or denial of service after the HTTP WebSocket upgrade handshake. This issue is fixed in version 4.8.1.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-50161.json)