CVE-2025-21597
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.
At a glance
- Exploitability
- Can be exploited from the same network segment without logging in. High risk of service disruption.
- Exploit odds
- 0.3% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.3% in the next 30 days (EPSS).
- Severity: 6.0 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.3% · EPSS, next 30 days
- Weakness
- CWE-754
- Record status
- Analyzed
Affected
- Juniper Junos < 20.4
- Juniper Junos 20.4
- Juniper Junos 21.2
- Juniper Junos 21.3
- Juniper Junos 21.4
- Juniper Junos 22.1
- Juniper Junos 22.2
- Juniper Junos 22.3
Attack profile CVSS 4.0 · 6.0
- Attack vector
- Adjacent network
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:A/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2025-21597.md and follow it. Check whether this project is affected by CVE-2025-21597. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
