CVE-2023-4481Network attack vector

BGP session interruption via malformed UPDATE handling

Published Aug 31, 2023 · Updated Oct 2, 2024

Improper input validation in Junos OS and Junos OS Evolved rpd allows remote attackers to reset BGP sessions with crafted UPDATE messages. The BGP message handler accepts a specific malformed UPDATE and handles it as an error that tears down a session; repeated messages sustain the interruption and propagate through unaffected speakers. The target must run IPv4 or IPv6 BGP, and the attacker must have at least one established eBGP or iBGP session, including a session to an intermediate speaker.

CVSS severity7.5
High
EPSS probability18.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Junos OS and Junos OS Evolved rpd allows remote attackers to reset BGP sessions with crafted UPDATE messages. The BGP message handler accepts a specific malformed UPDATE and handles it as an error that tears down a session; repeated messages sustain the interruption and propagate through unaffected speakers. The target must run IPv4 or IPv6 BGP, and the attacker must have at least one established eBGP or iBGP session, including a session to an intermediate speaker.

The record

CVE
CVE-2023-4481
Published
Aug 31, 2023
Updated
Oct 2, 2024
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-20, CAPEC-28, T1498
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 2, 2024Record 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 <20.4R3-S10-EVO
  2. Affected versionversion=21.2-EVO <21.2R3-S7-EVO
  3. Affected versionversion=21.3-EVO <21.3R3-S5-EVO
  4. Affected versionversion=21.4-EVO <21.4R3-S5-EVO
  5. Affected versionversion=22.1-EVO <22.1R3-S4-EVO
  6. Affected versionversion=22.2-EVO <22.2R3-S3-EVO
  7. Affected versionversion=22.3-EVO <22.3R3-S1-EVO
  8. Affected versionversion=22.4-EVO <22.4R3-EVO
  9. Affected versionversion=23.2-EVO <23.2R2-EVO

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=0 <20.4R3-S10-EVO; version=21.2-EVO <21.2R3-S7-EVO; version=21.3-EVO <21.3R3-S5-EVO; version=21.4-EVO <21.4R3-S5-EVO; version=22.1-EVO <22.1R3-S4-EVO; version=22.2-EVO <22.2R3-S3-EVO; version=22.3-EVO <22.3R3-S1-EVO; version=22.4-EVO <22.4R3-EVO; version=23.2-EVO <23.2R2-EVO
Juniper Networks · Junos OSversion=0 <20.4R3-S10; version=21.1R1 <=21.*; version=21.1R1 <21.*; version=21.2 <21.2R3-S5; version=21.3 <21.3R3-S5; version=21.4 <21.4R3-S7; version=21.4 <21.4R3-S7 changes=[{"at":"21.4R3-S5","status":"unaffected"},{"at":"21.4R3-S6","status":"affected"}]; version=22.1 <22.1R3-S4; version=22.2 <22.2R3-S3; version=22.3 <22.3R3-S1; version=22.4 <22.4R3; version=23.2 <23.2R2

Published CVSS scores

7.5Juniper NetworksCVSS: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

CWE-20Improper Input Validation
CAPEC-28Fuzzing
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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