Key points
- CVE-2026-101982 is rated critical with a CVSS score of 9.8.
- The vulnerability affects Junos OS and Junos OS Evolved routing daemons.
- Attackers can exploit the flaw using protocol-valid EVPN-VPWS route advertisements.
A critical stack-based buffer overflow in Juniper Networks Junos OS and Junos OS Evolved exposes organizations to root code execution. The flaw, tracked as CVE-2026-101982, resides in the routing protocol daemon. According to the National Vulnerability Database, a configured BGP or EVPN peer can trigger the issue. This affects managed service providers and enterprises relying on these network operating systems for core routing infrastructure.
By the numbers
- CVSS 9.8: The maximum severity rating assigned to this vulnerability by the National Vulnerability Database.
- CWE-121: The Common Weakness Enumeration identifier for the stack-based buffer overflow weakness.
- 12 versions: The count of specific Junos OS and Junos OS Evolved releases identified as affected.
What the figures mean
The high severity score indicates that exploitation is technically feasible and the impact is severe. The vulnerability allows an attacker with a configured BGP or EVPN peer relationship to send specific route advertisements. These advertisements are protocol-valid for an EVPN-VPWS service but contain data that overflows the stack buffer. On standard Junos OS, this results in root code execution. On Junos OS Evolved, the same action causes the routing protocol daemon to crash, leading to service disruption.
What should you do?
Network teams should immediately inventory all devices running Junos OS or Junos OS Evolved. Compare installed versions against the affected lists provided by the vendor. Prioritize remediation for devices exposed to untrusted BGP or EVPN peers. Ensure that configuration backups are current before applying any changes. Monitor system logs for unusual daemon restarts or unexpected process behavior that could indicate exploitation attempts.
Operational impact
Organizations must determine which internal teams hold visibility into BGP and EVPN peering configurations. Network operations centers need to verify if any peers are sending EVPN-VPWS advertisements that could trigger the overflow. Security operations should check whether existing monitoring rules detect anomalous routing updates. Procurement teams should review supplier contracts to ensure vendors are notified of critical infrastructure vulnerabilities. Leadership must be informed of potential service risks to maintain business continuity planning.
What to do and how to stay safe: Juniper Networks
- Audit all Juniper devices to identify those running versions prior to the specified secure releases.
- Restrict BGP and EVPN peering to trusted partners only to reduce the attack surface.
- Monitor routing daemon logs for crashes or unexpected termination events on Junos OS Evolved.
- Prepare incident response plans for potential root compromise or service outage scenarios.
General security guidance from the BitShield News newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Which Juniper operating systems are affected by this vulnerability?
Junos OS and Junos OS Evolved are both affected by the stack-based buffer overflow in the routing protocol daemon.
What is the impact on Junos OS Evolved devices?
On Junos OS Evolved, the vulnerability causes the routing protocol daemon to crash rather than allowing root code execution.
Is there a fix available for CVE-2026-101982?
The source material lists affected versions but does not confirm the availability of a patch or update.
