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Fencer Vulns
high 7.5

CVE-2023-4481 in the critical feed json

Junos OS and Junos OS Evolved: A crafted BGP UPDATE message allows a remote attacker to de-peer (reset) BGP sessions (CVE-2023-4481)

published 2023-08-31 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-54336

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
18.4%
EPSS 18.4% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

An Improper Input Validation vulnerability in the Routing Protocol Daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS).

When certain specific crafted BGP UPDATE messages are received over an established BGP session, one BGP session may be torn down with an UPDATE message error, or the issue may propagate beyond the local system which will remain non-impacted, but may affect one or more remote systems. This issue is exploitable remotely as the crafted UPDATE message can propagate through unaffected systems and intermediate BGP speakers. Continuous receipt of the crafted BGP UPDATE messages will create a sustained Denial of Service (DoS) condition for impacted devices.

This issue affects eBGP and iBGP, in both IPv4 and IPv6 implementations. This issue requires a remote attacker to have at least one established BGP session. Improper Input Validation, Denial of Service vulnerability in Juniper Networks, Inc. Junos OS (BGP, rpd modules), Juniper Networks, Inc. Junos OS Evolved (BGP, rpd modules) allows Fuzzing.This issue affects

Junos OS:

* All versions before 20.4R3-S10, * from 21.1R1 through 21.*, * from 21.2 before 21.2R3-S5, * from 21.3 before 21.3R3-S5, * from 21.4 before 21.4R3-S7 (unaffected from 21.4R3-S5, affected from 21.4R3-S6) * from 22.1 before 22.1R3-S4, * from 22.2 before 22.2R3-S3, * from 22.3 before 22.3R3-S1, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2.

Junos OS Evolved:

* All versions before 20.4R3-S10-EVO, * from 21.2-EVO before 21.2R3-S7-EVO, * from 21.3-EVO before 21.3R3-S5-EVO, * from 21.4-EVO before 21.4R3-S5-EVO, * from 22.1-EVO before 22.1R3-S4-EVO, * from 22.2-EVO before 22.2R3-S3-EVO, * from 22.3-EVO before 22.3R3-S1-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO.

Patch / fix

  • Juniper Networks, Inc. Junos OS 20.4R3-S10, 21.2R3-S5, 21.3R3-S5, 21.4R3-S5, 21.4R3-S7, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1, 22.4R3, 23.2R2
  • Juniper Networks, Inc. Junos OS Evolved 20.4R3-S10-EVO, 21.2R3-S7-EVO, 21.3R3-S5-EVO, 21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S3-EVO, 22.3R3-S1-EVO, 22.4R3-EVO, 23.2R2-EVO
  • juniper_networks junos_os 20.4R3-S10, 21.2R3-S5, 21.3R3-S5, 21.4R3-S7, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1, 22.4R3, 23.2R2
  • juniper_networks junos_os_evolved 20.4R3-S10-EVO, 21.2R3-S7-EVO, 21.3R3-S5-EVO, 21.4R3-S5-EVO, 22.1R3-S4-EVO, 22.2R3-S3-EVO, 22.3R3-S1-EVO, 22.4R3-EVO, 23.2R2-EVO

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

18.35% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Juniper Networks, Inc. Junos OS
  • Juniper Networks, Inc. Junos OS Evolved
  • juniper_networks junos_os
  • juniper_networks junos_os_evolved

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.