GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Versions prior to 4.6.0 contain a BGP OPEN capability parsing issue where several concrete capability decoders may parse data from the full remaining capability buffer instead of the slice bounded by the declared capability length, `CapLen`. A malformed BGP OPEN message can cause bytes from a following capability to be interpreted as part of the current capability. The most security-relevant case is the 4-octet AS capability, where a capability with `CapLen == 0` may cause the parser to read bytes from the following capability as the 4-octet AS value. This parsed value may later affect peer AS validation during BGP session establishment. Version 4.6.0 patches the issue.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-gjrg-jjr3-56cm GoBGP: BGP OPEN capability parser may read capability values outside declared CapLen boundaries
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 11 Sep 2026 07:45:00 +0000

Type Values Removed Values Added
First Time appeared Osrg
Osrg gobgp
Vendors & Products Osrg
Osrg gobgp

Thu, 10 Sep 2026 22:00:00 +0000

Type Values Removed Values Added
Description GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Versions prior to 4.6.0 contain a BGP OPEN capability parsing issue where several concrete capability decoders may parse data from the full remaining capability buffer instead of the slice bounded by the declared capability length, `CapLen`. A malformed BGP OPEN message can cause bytes from a following capability to be interpreted as part of the current capability. The most security-relevant case is the 4-octet AS capability, where a capability with `CapLen == 0` may cause the parser to read bytes from the following capability as the 4-octet AS value. This parsed value may later affect peer AS validation during BGP session establishment. Version 4.6.0 patches the issue.
Title GoBGP: BGP OPEN capability parser may read capability values outside declared CapLen boundaries
Weaknesses CWE-125
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-10T21:56:13.637Z

Reserved: 2026-06-01T18:50:36.056Z

Link: CVE-2026-49837

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-10T22:16:57.507

Modified: 2026-09-10T22:16:57.507

Link: CVE-2026-49837

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-11T07:30:09Z

Weaknesses