CVE-2025-21602

Routing-service interruption via exceptional BGP update handling

Published Jan 9, 2025 · Updated Jan 9, 2025

Improper exception handling in rpd in Juniper Networks Junos OS and Junos OS Evolved allows attackers to restart rpd via BGP. The daemon improperly handles an exceptional condition while processing a specific BGP update, terminating and automatically restarting instead of rejecting the packet. An unauthenticated adjacent BGP peer can repeatedly send the packet to sustain the service interruption; iBGP, eBGP, IPv4, and IPv6 are affected.

CVSS severity7.1
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exception handling in rpd in Juniper Networks Junos OS and Junos OS Evolved allows attackers to restart rpd via BGP. The daemon improperly handles an exceptional condition while processing a specific BGP update, terminating and automatically restarting instead of rejecting the packet. An unauthenticated adjacent BGP peer can repeatedly send the packet to sustain the service interruption; iBGP, eBGP, IPv4, and IPv6 are affected.

The record

CVE
CVE-2025-21602
Published
Jan 9, 2025
Updated
Jan 9, 2025
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-755, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Jan 9, 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=21.4 <21.4R3-S9-EVO
  2. Affected versionversion=22.2 <22.2R3-S5-EVO
  3. Affected versionversion=22.3 <22.3R3-S4-EVO
  4. Affected versionversion=22.4 <22.4R3-S5-EVO
  5. Affected versionversion=23.2 <23.2R2-S3-EVO
  6. Affected versionversion=23.4 <23.4R2-S3-EVO
  7. Affected versionversion=24.2 <24.2R1-S2-EVO, 24.2R2-EVO

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=21.4 <21.4R3-S9-EVO; version=22.2 <22.2R3-S5-EVO; version=22.3 <22.3R3-S4-EVO; version=22.4 <22.4R3-S5-EVO; version=23.2 <23.2R2-S3-EVO; version=23.4 <23.4R2-S3-EVO; version=24.2 <24.2R1-S2-EVO, 24.2R2-EVO
Juniper Networks · Junos OSversion=21.4 <21.4R3-S9; version=22.2 <22.2R3-S5; version=22.3 <22.3R3-S4; version=22.4 <22.4R3-S5; version=23.2 <23.2R2-S3; version=23.4 <23.4R2-S3; version=24.2 <24.2R1-S2, 24.2R2

Published CVSS scores

6.5Juniper NetworksCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.1Juniper NetworksCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:N/R:A/V:C/RE:M/U:Green

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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