CVE-2025-21597

MEDIUM
Published Apr 9, 2025 Modified Jan 26, 2026 CWE-754

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.

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CVSS v3.1 Score

5.3
MEDIUM
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-754 CWE-754

Affected Products

Vendor Product
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
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juniper junos
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juniper junos
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juniper junos
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juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
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juniper junos_os_evolved
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juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved

References

Advisories & Patches

Frequently Asked Questions

What is CVE-2025-21597? +
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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2025-21597? +
CVE-2025-21597 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2025-21597? +
CVE-2025-21597 affects products from juniper, specifically: junos, junos_os_evolved. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-21597? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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