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.
zetlyn/cve-nvd vulnerability cve CVE-2026-49837 known 2026-09-10
https://nvd.nist.gov/vuln/detail/CVE-2026-49837
Properties
| cvss | 5.9receipt
What the source handed over{
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"affected": [
{
"affectedData": [
{
"product": "gobgp",
"vendor": "osrg",
"versions": [
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}
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} | ||||
|---|---|---|---|---|---|
| product | gobgpreceipt
What the source handed over{
"cve": {
"affected": [
{
"affectedData": [
{
"product": "gobgp",
"vendor": "osrg",
"versions": [
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}
],
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} | ||||
| status | Deferredreceipt
What the source handed over{
"cve": {
"affected": [
{
"affectedData": [
{
"product": "gobgp",
"vendor": "osrg",
"versions": [
{
"status": "affected",
"version": "< 4.6.0"
}
]
}
],
"source": "security-advisories@github.com"
}
],
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{
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"value": "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": "CVE-2026-49837",
"lastModified": "2026-09-16T13:42:46.953",
"metrics": {
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"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
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} | ||||
| vendor | osrgreceipt
What the source handed over{
"cve": {
"affected": [
{
"affectedData": [
{
"product": "gobgp",
"vendor": "osrg",
"versions": [
{
"status": "affected",
"version": "< 4.6.0"
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}
],
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} |
Text
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.