CVE-2025-21597

Junos OS and Junos OS Evolved: When BGP rib-sharding and update-threading are configured and a peer flaps, an rpd core is observed

MEDIUM

5.3

CVSS Score

Published: April 9, 2025 at 07:50 PM UTC

Updated: June 17, 2026 at 08:43 AM UTC

3 products affected across 2 vendorsJunosJunos OS EvolvedJunos OS Evolved

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Severity

MEDIUM5.3

Exploit prediction

EPSS 0.2%

SSVC

No known exploit

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, logically adjacent BGP peer to cause Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, when BGP rib-sharding and update-threading are configured, and a BGP peer flap is done with specific timing, rpd crashes and restarts. Continuous peer flapping at specific time intervals will result in a sustained Denial of Service (DoS) condition. 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. The issue can occur with or without logical-systems enabled. This issue affects: Junos OS: * All versions before 20.4R3-S8, * 21.2 versions before 21.2R3-S6, * 21.3 versions before 21.3R3-S5, * 21.4 versions before 21.4R3-S4, * 22.1 versions before 22.1R3-S3, * 22.2 versions before 22.2R3-S1, * 22.3 versions before 22.3R3, * 22.4 versions before 22.4R3. Junos OS Evolved: * All versions before 21.2R3-S6-EVO, * 21.3-EVO versions before 21.3R3-S5-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.1-EVO versions before 22.1R3-S3-EVO, * 22.2-EVO versions before :22.2R3-S1-EVO, * 22.3-EVO versions before 22.3R3-EVO, * 22.4-EVO versions before 22.4R3-EVO.

Affected

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

Junos · Juniper Networks

95%

v < 20.4v < 20.4R3-S821.2 ≤ v < 21.2R3-S621.3 ≤ v < 21.3R3-S521.4 ≤ v < 21.4R3-S422.1 ≤ v < 22.1R3-S322.2 ≤ v < 22.2R3-S122.3 ≤ v < 22.3R322.4 ≤ v < 22.4R320.4 20.4 r1 20.4 r1-s1 20.4 r2 20.4 r2-s1 20.4 r2-s2 20.4 r3 20.4 r3-s1 20.4 r3-s2 20.4 r3-s3 20.4 r3-s4 20.4 r3-s5 20.4 r3-s6 20.4 r3-s7 21.2 21.2 r1 21.2 r1-s1 21.2 r1-s2 21.2 r2 21.2 r2-s1 21.2 r2-s2 21.2 r3 21.2 r3-s1 21.2 r3-s2 21.2 r3-s3 21.2 r3-s4 21.2 r3-s5 21.3 21.3 r1 21.3 r1-s1 21.3 r1-s2 21.3 r2 21.3 r2-s1 21.3 r2-s2 21.3 r3 21.3 r3-s1 21.3 r3-s2 21.3 r3-s3 21.3 r3-s4 21.4 21.4 r1 21.4 r1-s1 21.4 r1-s2 21.4 r2 21.4 r2-s1 21.4 r2-s2 21.4 r3 21.4 r3-s1 21.4 r3-s2 21.4 r3-s3 22.1 22.1 r1 22.1 r1-s1 22.1 r1-s2 22.1 r2 22.1 r2-s1 22.1 r2-s2 22.1 r3 22.1 r3-s1 22.1 r3-s2 22.2 22.2 r1 22.2 r1-s1 22.2 r1-s2 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.2 r3 22.3 22.3 r1 22.3 r1-s1 22.3 r1-s2 22.3 r2 22.3 r2-s1 22.3 r2-s2 22.4 22.4 r1 22.4 r1-s1 22.4 r1-s2 22.4 r2 22.4 r2-s1 22.4 r2-s2

Affected range stops below 20.4R3-S8, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.2R3-S6, 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-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.1R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3-S1, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.3R3, 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

Junos OS Evolved · Juniper Networks

60%

v < 21.2R3-S6-EVO21.3-EVO ≤ v < 21.3R3-S5-EVO21.4-EVO ≤ v < 21.4R3-S4-EVO22.1-EVO ≤ v < 22.1R3-S3-EVO22.2-EVO ≤ v < 22.2R3-S1-EVO22.3-EVO ≤ v < 22.3R3-EVO22.4-EVO ≤ v < 22.4R3-EVO21.3-EVO 21.4-EVO 22.1-EVO 22.2-EVO 22.3-EVO 22.4-EVO

Affected range stops below 21.2R3-S6-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-S4-EVO, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.1R3-S3-EVO, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3-S1-EVO, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.3R3-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

Remediation

No guide yet

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

Patch and advisory references

https://kb.juniper.net/JSA96451

References (1)

Vendor Advisory

Source: [email protected]

https://kb.juniper.net/JSA96451

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

5.3MEDIUMjuniper

Attack Vector: ADJACENT_NETWORK
Complexity: HIGH
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusANALYZED

CWE

CWE-754

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