CVE-2023-38407Network attack vector

Daemon crash via undersized labeled-unicast NLRI

Published Nov 6, 2023 · Updated Nov 4, 2025

Out-of-bounds read in FRRouting before 8.5 allows remote attackers to crash bgpd via a malformed labeled-unicast BGP update. bgp_nlri_get_labels accepts a label field shorter than three bytes, while the parser also advances past an absent Add-Path identifier before reading. A reachable, established BGP peer that sends the malformed NLRI can interrupt routing until the daemon recovers or restarts.

CVSS severity7.5
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in FRRouting before 8.5 allows remote attackers to crash bgpd via a malformed labeled-unicast BGP update. bgp_nlri_get_labels accepts a label field shorter than three bytes, while the parser also advances past an absent Add-Path identifier before reading. A reachable, established BGP peer that sends the malformed NLRI can interrupt routing until the daemon recovers or restarts.

The record

CVE
CVE-2023-38407
Published
Nov 6, 2023
Updated
Nov 4, 2025
Vendor
FRRouting
Product
FRRouting
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 6, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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=0 <8.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FRRouting · FRRoutingversion=0 <8.5

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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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