CVE-2026-49838 MEDIUM

CVE-2026-49838: GoBGP confederation validation panics on empty AS_PATH attribute

Vendor Osrg
Product gobgp
Weakness CWE-129
Published September 10, 2026
Last update September 10, 2026
View on NVD All CVEs

CVSS base score

5.9/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

September 10, 2026 CVE published