A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability the
Routing Protocol Daemon (rpd)
of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to inject incremental routing updates when BGP multipath is enabled, causing rpd to crash and restart, resulting in a Denial of Service (DoS). Since this is a timing issue (race condition), the successful exploitation of this vulnerability is outside the attacker's control. However, continued receipt and processing of this packet may create a sustained Denial of Service (DoS) condition.
On all Junos OS and Junos OS Evolved platforms with BGP multipath enabled, a specific multipath calculation removes the original next hop from the multipath lead routes nexthop-set. When this change happens, multipath relies on certain internal timing to record the update. Under certain circumstance and with specific timing, this could result in an rpd crash.
This issue only affects systems with BGP multipath enabled.
This issue affects:
Junos OS:
Junos OS Evolved:
Versions of Junos OS before 21.1R1 are unaffected by this vulnerability. Versions of Junos OS Evolved before 21.1R1-EVO are unaffected by this vulnerability.
| Software | From | Fixed in |
|---|---|---|
| juniper / junos | 21.2-r1 | 21.2-r1.x |
| juniper / junos | 21.2-r1-s1 | 21.2-r1-s1.x |
| juniper / junos | 21.2-r2 | 21.2-r2.x |
| juniper / junos | 21.2 | 21.2.x |
| juniper / junos | 21.2-r1-s2 | 21.2-r1-s2.x |
| juniper / junos | 21.2-r2-s1 | 21.2-r2-s1.x |
| juniper / junos | 21.2-r2-s2 | 21.2-r2-s2.x |
| juniper / junos | 21.2-r3 | 21.2-r3.x |
| juniper / junos | 21.4 | 21.4.x |
| juniper / junos | 21.4-r1 | 21.4-r1.x |
| juniper / junos | 21.4-r1-s1 | 21.4-r1-s1.x |
| juniper / junos | 21.4-r1-s2 | 21.4-r1-s2.x |
| juniper / junos | 21.4-r2 | 21.4-r2.x |
| juniper / junos | 21.4-r2-s1 | 21.4-r2-s1.x |
| juniper / junos | 22.1-r1 | 22.1-r1.x |
| juniper / junos_os_evolved | 21.4 | 21.4.x |
| juniper / junos_os_evolved | 21.4-r1 | 21.4-r1.x |
| juniper / junos_os_evolved | 21.4-r1-s1 | 21.4-r1-s1.x |
| juniper / junos | 21.2-r3-s1 | 21.2-r3-s1.x |
| juniper / junos | 21.2-r3-s2 | 21.2-r3-s2.x |
| juniper / junos | 21.4-r2-s2 | 21.4-r2-s2.x |
| juniper / junos | 21.4-r3 | 21.4-r3.x |
| juniper / junos | 22.1-r1-s1 | 22.1-r1-s1.x |
| juniper / junos | 22.1-r1-s2 | 22.1-r1-s2.x |
| juniper / junos | 22.1-r2 | 22.1-r2.x |
| juniper / junos | 22.1-r2-s2 | 22.1-r2-s2.x |
| juniper / junos | 22.2-r1 | 22.2-r1.x |
| juniper / junos | 22.2-r1-s1 | 22.2-r1-s1.x |
| juniper / junos | 22.2-r2 | 22.2-r2.x |
| juniper / junos | 22.3-r1 | 22.3-r1.x |
| juniper / junos_os_evolved | 21.4-r1-s2 | 21.4-r1-s2.x |
| juniper / junos_os_evolved | 21.4-r2 | 21.4-r2.x |
| juniper / junos_os_evolved | 21.4-r2-s1 | 21.4-r2-s1.x |
| juniper / junos_os_evolved | 21.4-r2-s2 | 21.4-r2-s2.x |
| juniper / junos_os_evolved | 21.4-r3 | 21.4-r3.x |
| juniper / junos_os_evolved | 22.1-r1 | 22.1-r1.x |
| juniper / junos_os_evolved | 22.1-r1-s1 | 22.1-r1-s1.x |
| juniper / junos_os_evolved | 22.1-r1-s2 | 22.1-r1-s2.x |
| juniper / junos_os_evolved | 22.1-r2 | 22.1-r2.x |
| juniper / junos_os_evolved | 22.2-r1 | 22.2-r1.x |
| juniper / junos_os_evolved | 22.2-r1-s1 | 22.2-r1-s1.x |
| juniper / junos_os_evolved | 22.3-r1 | 22.3-r1.x |
| juniper / junos | 21.2-r3-s3 | 21.2-r3-s3.x |
| juniper / junos | 21.2-r3-s4 | 21.2-r3-s4.x |
| juniper / junos | 21.2-r3-s5 | 21.2-r3-s5.x |
| juniper / junos | 21.2-r3-s6 | 21.2-r3-s6.x |
| juniper / junos | 21.4-r3-s1 | 21.4-r3-s1.x |
| juniper / junos | 21.4-r3-s2 | 21.4-r3-s2.x |
| juniper / junos | 21.4-r3-s3 | 21.4-r3-s3.x |
| juniper / junos | 21.4-r3-s4 | 21.4-r3-s4.x |
| juniper / junos | 22.1-r2-s1 | 22.1-r2-s1.x |
| juniper / junos | 22.1-r3 | 22.1-r3.x |
| juniper / junos | 22.1-r3-s1 | 22.1-r3-s1.x |
| juniper / junos | 22.1-r3-s2 | 22.1-r3-s2.x |
| juniper / junos | 22.1-r3-s3 | 22.1-r3-s3.x |
| juniper / junos | 22.2-r1-s2 | 22.2-r1-s2.x |
| juniper / junos | 22.2-r2-s1 | 22.2-r2-s1.x |
| juniper / junos | 22.2-r2-s2 | 22.2-r2-s2.x |
| juniper / junos | 22.2-r3 | 22.2-r3.x |
| juniper / junos | 22.2-r3-s1 | 22.2-r3-s1.x |
| juniper / junos | 22.3-r1-s1 | 22.3-r1-s1.x |
| juniper / junos | 22.3-r1-s2 | 22.3-r1-s2.x |
| juniper / junos | 22.3-r2 | 22.3-r2.x |
| juniper / junos | 22.3-r2-s1 | 22.3-r2-s1.x |
| juniper / junos | 22.4-r1 | 22.4-r1.x |
| juniper / junos | 22.4-r1-s1 | 22.4-r1-s1.x |
| juniper / junos | 22.4-r1-s2 | 22.4-r1-s2.x |
| juniper / junos | 22.4-r2 | 22.4-r2.x |
| juniper / junos | 23.2-r1 | 23.2-r1.x |
| juniper / junos_os_evolved | 21.4-r3-s1 | 21.4-r3-s1.x |
| juniper / junos_os_evolved | 21.4-r3-s2 | 21.4-r3-s2.x |
| juniper / junos_os_evolved | 21.4-r3-s3 | 21.4-r3-s3.x |
| juniper / junos_os_evolved | 22.1-r2-s1 | 22.1-r2-s1.x |
| juniper / junos_os_evolved | 22.1-r3 | 22.1-r3.x |
| juniper / junos_os_evolved | 22.1-r3-s1 | 22.1-r3-s1.x |
| juniper / junos_os_evolved | 22.1-r3-s2 | 22.1-r3-s2.x |
| juniper / junos_os_evolved | 22.1-r3-s3 | 22.1-r3-s3.x |
| juniper / junos_os_evolved | 22.2-r2 | 22.2-r2.x |
| juniper / junos_os_evolved | 22.2-r2-s1 | 22.2-r2-s1.x |
| juniper / junos_os_evolved | 22.2-r2-s2 | 22.2-r2-s2.x |
| juniper / junos_os_evolved | 22.2-r3 | 22.2-r3.x |
| juniper / junos_os_evolved | 22.2-r3-s1 | 22.2-r3-s1.x |
| juniper / junos_os_evolved | 22.3-r1-s1 | 22.3-r1-s1.x |
| juniper / junos_os_evolved | 22.3-r1-s2 | 22.3-r1-s2.x |
| juniper / junos_os_evolved | 22.3-r2 | 22.3-r2.x |
| juniper / junos_os_evolved | 22.3-r2-s1 | 22.3-r2-s1.x |
| juniper / junos_os_evolved | 22.4-r1 | 22.4-r1.x |
| juniper / junos_os_evolved | 22.4-r1-s1 | 22.4-r1-s1.x |
| juniper / junos_os_evolved | 22.4-r1-s2 | 22.4-r1-s2.x |
| juniper / junos_os_evolved | 22.4-r2 | 22.4-r2.x |
| juniper / junos | 21.1 | 21.2 |
| juniper / junos | 21.4-r3-s5 | 21.4-r3-s5.x |
| juniper / junos | 22.1 | 22.1.x |
| juniper / junos | 22.1-r3-s4 | 22.1-r3-s4.x |
| juniper / junos | 22.2 | 22.2.x |
| juniper / junos | 22.2-r3-s2 | 22.2-r3-s2.x |
| juniper / junos | 22.3 | 22.3.x |
| juniper / junos | 22.3-r2-s2 | 22.3-r2-s2.x |
| juniper / junos | 22.3-r3 | 22.3-r3.x |
| juniper / junos | 22.3-r3-s1 | 22.3-r3-s1.x |
| juniper / junos | 22.4 | 22.4.x |
| juniper / junos | 22.4-r2-s1 | 22.4-r2-s1.x |
| juniper / junos | 22.4-r2-s2 | 22.4-r2-s2.x |
| juniper / junos | 23.2 | 23.2.x |
| juniper / junos | 23.2-r1-s1 | 23.2-r1-s1.x |
| juniper / junos | 23.2-r1-s2 | 23.2-r1-s2.x |
| juniper / junos_os_evolved | 21.1 | 21.3 |
| juniper / junos_os_evolved | 21.4-r3-s4 | 21.4-r3-s4.x |
| juniper / junos_os_evolved | 21.4-r3-s5 | 21.4-r3-s5.x |
| juniper / junos_os_evolved | 22.1 | 22.1.x |
| juniper / junos_os_evolved | 22.1-r3-s4 | 22.1-r3-s4.x |
| juniper / junos_os_evolved | 22.2 | 22.2.x |
| juniper / junos_os_evolved | 22.2-r1-s2 | 22.2-r1-s2.x |
| juniper / junos_os_evolved | 22.2-r3-s2 | 22.2-r3-s2.x |
| juniper / junos_os_evolved | 22.3 | 22.3.x |
| juniper / junos_os_evolved | 22.3-r2-s2 | 22.3-r2-s2.x |
| juniper / junos_os_evolved | 22.3-r3 | 22.3-r3.x |
| juniper / junos_os_evolved | 22.3-r3-s1 | 22.3-r3-s1.x |
| juniper / junos_os_evolved | 22.4 | 22.4.x |
| juniper / junos_os_evolved | 22.4-r2-s1 | 22.4-r2-s1.x |
| juniper / junos_os_evolved | 22.4-r2-s2 | 22.4-r2-s2.x |
| juniper / junos_os_evolved | 23.2 | 23.2.x |
| juniper / junos_os_evolved | 23.2-r1 | 23.2-r1.x |
| juniper / junos_os_evolved | 23.2-r1-s1 | 23.2-r1-s1.x |
| juniper / junos_os_evolved | 23.2-r1-s2 | 23.2-r1-s2.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.