---
id: CVE-2026-49838
title: >-
  GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go
  Programming Language
summary: >-
  GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go
  Programming Language. Prior to version 4.7.0, GoBGP accepts a zero-length
  AS_PATH during UPDATE decoding and later panics while validating that
  attribute for …
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-129
  - CWE-125
vendor: osrg
product: gobgp
affected:
  - gobgp < 4.7.0
patched:
  - github.com/osrg/gobgp/v4 4.7.0
published: '2026-09-10'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T13:42:46.970'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-49838'
references:
  - url: >-
      https://github.com/osrg/gobgp/commit/4a319a6c25630fb3cdbda3e9ccfe56e702bdaaa0
    label: security-advisories@github.com
  - url: 'https://github.com/osrg/gobgp/security/advisories/GHSA-frrj-87jh-2772'
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-frrj-87jh-2772'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49838.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-49838'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2531686'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-49838'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-49838'
tags:
  - nvd
  - cve.org
  - ghsa
  - go
  - csaf
  - vex
  - red-hat
epss: 0.00412
epssPercentile: 0.32783
aliases:
  - GHSA-frrj-87jh-2772
ecosystem: go
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-11T16:31:55.831766Z'
ingestedAt: '2026-07-09T23:53:27.206Z'
---

## Overview

GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Prior to version 4.7.0, GoBGP accepts a zero-length AS_PATH during UPDATE decoding and later panics while validating that attribute for a confederation eBGP peer. The vulnerable path is in the BGP UPDATE validator: a malformed UPDATE that should be rejected as a malformed AS_PATH instead reaches an unchecked `p.Value[0]` access, allowing a configured confederation eBGP peer to trigger a denial of service. Version 4.7.0 patches the issue.

## Remediation

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

## Package advisory (CVE-2026-49838)

Affected packages:

- `github.com/osrg/gobgp/v4 <= 4.6.0`

Patched in:

- `github.com/osrg/gobgp/v4 4.7.0`

Source: https://github.com/advisories/GHSA-frrj-87jh-2772

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat OpenShift Container Platform 4 · updated 2026-09-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49838.json)