CVE-2023-4481

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

HIGH
7.5
CVSS Score
Published: August 31, 2023 at 11:46 PM UTC
Updated: June 17, 2026 at 06:37 AM UTC
3 products affected across 2 vendorsJunosJunos OS EvolvedJunos OS Evolved

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Severity
HIGH7.5
Exploit prediction
EPSS 18%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Affected range stops below 20.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 20.4R3-S10, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.*, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.2R3-S5, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.3R3-S5, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.4R3-S7, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.1R3-S4, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.2R3-S3, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.3R3-S1, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.4R3, so it looks safe — our inference, not a vendor statement
Affected range stops below 23.2R2, so it looks safe — our inference, not a vendor statement
v < 20.4R3-S10-EVO21.2-EVO ≤ v < 21.2R3-S7-EVO21.3-EVO ≤ v < 21.3R3-S5-EVO21.4-EVO ≤ v < 21.4R3-S5-EVO22.1-EVO ≤ v < 22.1R3-S4-EVO22.2-EVO ≤ v < 22.2R3-S3-EVO22.3-EVO ≤ v < 22.3R3-S1-EVO22.4-EVO ≤ v < 22.4R3-EVO23.2-EVO ≤ v < 23.2R2-EVO21.2-EVO21.3-EVO21.4-EVO22.1-EVO22.2-EVO22.3-EVO22.4-EVO23.2-EVO
Affected range stops below 20.4R3-S10-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.2R3-S7-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.3R3-S5-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 21.4R3-S5-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.1R3-S4-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.2R3-S3-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.3R3-S1-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.4R3-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 23.2R2-EVO, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHjuniper
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-20NVD-CWE-noinfo

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