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
First published: Wed Apr 09 2025(Updated: )
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.
Credit: sirt@juniper.net
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Juniper JUNOS | <20.4R3-S8<21.2R3-S6<21.3R3-S5<21.4R3-S4<22.1R3-S3<22.2R3-S1<22.3R3<22.4R3 | |
| Juniper Networks Junos OS | <21.2R3-S6-EVO<21.3R3-S5-EVO<21.4R3-S4-EVO<22.1R3-S3-EVO<22.2R3-S1-EVO<22.3R3-EVO<22.4R3-EVO |
Remedy
The following software releases have been updated to resolve this specific issue: Junos OS: 20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3, 22.2R3-S1, 22.3R3, 22.4R3, 23.2R1, and all subsequent releases. Junos OS Evolved: 21.2R3-S6-EVO, 21.3R3-S5-EVO, 21.4R3-S4-EVO, 22.1R3-S3-EVO, 22.2R3-S1-EVO, 22.3R3-EVO, 22.4R3-EVO, 23.2R1-EVO, and all subsequent releases.
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-21597?
CVE-2025-21597 has a high severity rating as it allows an unauthenticated BGP peer to cause a Denial of Service (DoS).
How do I fix CVE-2025-21597?
To remediate CVE-2025-21597, upgrade Junos OS or Junos OS Evolved to a version that addresses this vulnerability as specified by Juniper Networks.
What causes CVE-2025-21597?
CVE-2025-21597 is caused by an improper check for unusual or exceptional conditions in the routing protocol daemon (rpd) of affected Juniper Networks software.
Who is affected by CVE-2025-21597?
CVE-2025-21597 affects users of Junos OS and Junos OS Evolved versions below those specified in the provided remediation guidelines.
What should I do if I cannot update to a safe version for CVE-2025-21597?
If immediate updates are not possible for CVE-2025-21597, consider implementing network segmentation to limit exposure to vulnerable systems.
- collector/mitre-cve
- source/MITRE
- agent/weakness
- agent/references
- agent/title
- agent/remedy
- agent/description
- agent/first-publish-date
- agent/type
- agent/guess-ai
- agent/software-canonical-lookup
- agent/softwarecombine
- collector/nvd-api
- source/NVD
- agent/severity
- agent/last-modified-date
- agent/source
- agent/author
- agent/tags
- agent/event
- vendor/juniper networks
- canonical/juniper junos
- canonical/juniper networks junos os