CVE-2026-49838Public exploitNetwork attack vector

Denial of service via empty AS_PATH validation

Published Sep 10, 2026 · Updated Sep 10, 2026

Denial of service in OSRG GoBGP 4.6.0 and earlier allows remote attackers to crash a BGP session via a malformed UPDATE. The UPDATE decoder accepts a zero-length AS_PATH, and confederation eBGP validation indexes p.Value[0] without checking for an empty slice. The sender must be a configured confederation eBGP neighbor with an established BGP session; the demonstrated effect is receive-goroutine and peer-session loss, with possible process termination.

CVSS severity5.9
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OSRG GoBGP 4.6.0 and earlier allows remote attackers to crash a BGP session via a malformed UPDATE. The UPDATE decoder accepts a zero-length AS_PATH, and confederation eBGP validation indexes p.Value[0] without checking for an empty slice. The sender must be a configured confederation eBGP neighbor with an established BGP session; the demonstrated effect is receive-goroutine and peer-session loss, with possible process termination.

The record

CVE
CVE-2026-49838
Published
Sep 10, 2026
Updated
Sep 10, 2026
Vendor
GoBGP
Product
GoBGP
Classifications
CWE-129, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GoBGP · GoBGPversion=< 4.7.0

Published CVSS scores

5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-129Improper Validation of Array Index
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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