CVE-2026-49838 (GCVE-0-2026-49838)
Vulnerability from cvelistv5 – Published: 2026-09-10 21:57 – Updated: 2026-09-10 21:57
VLAI
EPSS
VEX
Title
GoBGP confederation validation panics on empty AS_PATH attribute
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 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.
Severity
5.9 (Medium)
CWE
- CWE-129 - Improper Validation of Array Index
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/osrg/gobgp/security/advisories… | x_refsource_CONFIRM |
| https://github.com/osrg/gobgp/commit/4a319a6c2563… | x_refsource_MISC |
{
"containers": {
"cna": {
"affected": [
{
"product": "gobgp",
"vendor": "osrg",
"versions": [
{
"status": "affected",
"version": "\u003c 4.7.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 5.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-129",
"description": "CWE-129: Improper Validation of Array Index",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-10T21:57:15.723Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/osrg/gobgp/security/advisories/GHSA-frrj-87jh-2772",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/osrg/gobgp/security/advisories/GHSA-frrj-87jh-2772"
},
{
"name": "https://github.com/osrg/gobgp/commit/4a319a6c25630fb3cdbda3e9ccfe56e702bdaaa0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/osrg/gobgp/commit/4a319a6c25630fb3cdbda3e9ccfe56e702bdaaa0"
}
],
"source": {
"advisory": "GHSA-frrj-87jh-2772",
"discovery": "UNKNOWN"
},
"title": "GoBGP confederation validation panics on empty AS_PATH attribute"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-49838",
"datePublished": "2026-09-10T21:57:15.723Z",
"dateReserved": "2026-06-01T18:50:36.056Z",
"dateUpdated": "2026-09-10T21:57:15.723Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-49838",
"date": "2026-09-11",
"epss": "0.00333",
"percentile": "0.26307"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-49838\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-09-10T22:16:57.660\",\"lastModified\":\"2026-09-10T22:16:57.660\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"osrg\",\"product\":\"gobgp\",\"versions\":[{\"version\":\"\u003c 4.7.0\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.9,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.2,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-129\"}]}],\"references\":[{\"url\":\"https://github.com/osrg/gobgp/commit/4a319a6c25630fb3cdbda3e9ccfe56e702bdaaa0\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/osrg/gobgp/security/advisories/GHSA-frrj-87jh-2772\",\"source\":\"security-advisories@github.com\"}]}}",
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-09-11T06:01:41+00:00",
"cve": "CVE-2026-49838",
"id": "CVE-2026-49838",
"initial_release_date": "2026-09-10T21:57:15.723000+00:00",
"product_status:known_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "github.com/osrg/gobgp: GoBGP: Denial of Service via malformed BGP UPDATE message",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-49838.json",
"version": "3"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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