UBUNTU-CVE-2026-49837 (CVE-2026-49837)
Vulnerability from osv_ubuntu – Published: 2026-09-10 22:16 – Updated: 2026-09-16 11:35 – Source website
VLAI
Details
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.
Severity
5.9 (Medium)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "gobgpd",
"binary_version": "1.29-1ubuntu0.1+esm2"
},
{
"binary_name": "golang-github-osrg-gobgp-dev",
"binary_version": "1.29-1ubuntu0.1+esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "gobgp",
"purl": "pkg:deb/ubuntu/gobgp@1.29-1ubuntu0.1+esm2?arch=source\u0026distro=esm-apps/bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.15-1",
"1.29-1",
"1.29-1ubuntu0.1+esm1",
"1.29-1ubuntu0.1+esm2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "gobgpd",
"binary_version": "2.12.0-1ubuntu0.1~esm3"
},
{
"binary_name": "golang-github-osrg-gobgp-dev",
"binary_version": "2.12.0-1ubuntu0.1~esm3"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:20.04:LTS",
"name": "gobgp",
"purl": "pkg:deb/ubuntu/gobgp@2.12.0-1ubuntu0.1~esm3?arch=source\u0026distro=esm-apps/focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.33-1",
"2.11.0-1",
"2.12.0-1",
"2.12.0-1ubuntu0.1~esm1",
"2.12.0-1ubuntu0.1~esm2",
"2.12.0-1ubuntu0.1~esm3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "gobgpd",
"binary_version": "2.25.0-3ubuntu0.1+esm4"
},
{
"binary_name": "golang-github-osrg-gobgp-dev",
"binary_version": "2.25.0-3ubuntu0.1+esm4"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:22.04:LTS",
"name": "gobgp",
"purl": "pkg:deb/ubuntu/gobgp@2.25.0-3ubuntu0.1+esm4?arch=source\u0026distro=esm-apps/jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.25.0-2",
"2.25.0-3",
"2.25.0-3build1",
"2.25.0-3ubuntu0.1",
"2.25.0-3ubuntu0.1+esm1",
"2.25.0-3ubuntu0.1+esm2",
"2.25.0-3ubuntu0.1+esm3",
"2.25.0-3ubuntu0.1+esm4"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "gobgpd",
"binary_version": "3.23.0-1ubuntu0.3+esm4"
},
{
"binary_name": "golang-github-osrg-gobgp-dev",
"binary_version": "3.23.0-1ubuntu0.3+esm4"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:24.04:LTS",
"name": "gobgp",
"purl": "pkg:deb/ubuntu/gobgp@3.23.0-1ubuntu0.3+esm4?arch=source\u0026distro=esm-apps/noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.16.0-1build1",
"3.19.0-1",
"3.21.0-1",
"3.23.0-1",
"3.23.0-1ubuntu0.1",
"3.23.0-1ubuntu0.2",
"3.23.0-1ubuntu0.2+esm1",
"3.23.0-1ubuntu0.3",
"3.23.0-1ubuntu0.3+esm1",
"3.23.0-1ubuntu0.3+esm2",
"3.23.0-1ubuntu0.3+esm3",
"3.23.0-1ubuntu0.3+esm4"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "gobgpd",
"binary_version": "3.36.0-2"
},
{
"binary_name": "golang-github-osrg-gobgp-dev",
"binary_version": "3.36.0-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "gobgp",
"purl": "pkg:deb/ubuntu/gobgp@3.36.0-2?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.35.0-1",
"3.36.0-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "gobgpd",
"binary_version": "3.36.0-2ubuntu0.1~esm1"
},
{
"binary_name": "golang-github-osrg-gobgp-dev",
"binary_version": "3.36.0-2ubuntu0.1~esm1"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:26.04:LTS",
"name": "gobgp",
"purl": "pkg:deb/ubuntu/gobgp@3.36.0-2ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.36.0-2",
"3.36.0-2build1",
"3.36.0-2ubuntu0.1~esm1"
]
}
],
"aliases": [],
"details": "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.",
"id": "UBUNTU-CVE-2026-49837",
"modified": "2026-09-16T11:35:35Z",
"published": "2026-09-10T22:16:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-49837"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-49837"
},
{
"type": "REPORT",
"url": "https://github.com/osrg/gobgp/security/advisories/GHSA-gjrg-jjr3-56cm"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-49837"
]
}
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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