Junos OS (SRX firewalls)
CVE-2025-21597: When BGP rib-sharding and update-threading are configured and a peer flaps, an rpd core is observed
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).
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS 0 | 20.4R3-S8 or later |
| Junos OS 21.2 | 21.2R3-S6 or later |
| Junos OS 21.3 | 21.3R3-S5 or later |
| Junos OS 21.4 | 21.4R3-S4 or later |
| Junos OS 22.1 | 22.1R3-S3 or later |
| Junos OS 22.2 | 22.2R3-S1 or later |
| Junos OS 22.3 | 22.3R3 or later |
| Junos OS 22.4 | 22.4R3 or later |
| Junos OS Evolved 0 | 21.2R3-S6-EVO or later |
| Junos OS Evolved 21.3-EVO | 21.3R3-S5-EVO or later |
| Junos OS Evolved 21.4-EVO | 21.4R3-S4-EVO or later |
| Junos OS Evolved 22.1-EVO | 22.1R3-S3-EVO or later |
| Junos OS Evolved 22.2-EVO | 22.2R3-S1-EVO or later |
| Junos OS Evolved 22.3-EVO | 22.3R3-EVO or later |
| Junos OS Evolved 22.4-EVO | 22.4R3-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Am I affected?
For this issue to occur, BGP rib-sharding and update-threading needs to be configured:
[system processes routing bgp rib-sharding] [system processes routing bgp update-threading]
Workarounds
There are no known workarounds for this issue.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.