# CVE-2026-101990: Juniper Junos OS stack buffer overflow in routing protocol daemon

Source: https://junglewise.ai/threats/cve-2026-101990-a-stack-based-buffer-overflow-vulnerability-in-the-routing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-14. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-101990 · Severity: critical · CVSS 9.8 · Published 2026-10-14

Juniper Junos OS is network operating system that manages enterprise routers and switches. A stack buffer overflow vulnerability in the routing protocol daemon allows a misconfigured BGP peer to crash the routing service or achieve remote code execution by sending specially crafted flow-specification updates, disrupting network operations or enabling full system compromise.

Technologies: [Juniper Networks Junos OS](https://junglewise.ai/threats/technologies/juniper-networks-junos-os), [Juniper Networks Junos OS Evolved](https://junglewise.ai/threats/technologies/junos-os-evolved). Vendors: [Juniper Networks](https://junglewise.ai/threats/vendors/juniper-networks).

## Quick answers

**Is CVE-2026-101990 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101990 being exploited in the wild.

**How severe is CVE-2026-101990?** Critical severity, with a CVSS score of 9.8, published 14 October 2026.

**Which products and versions are affected?** Juniper Networks Junos OS; Juniper Networks Junos OS Evolved.

**Is there a fix for CVE-2026-101990?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-101990 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-101990?** Check whether you run Juniper Networks Junos OS or Juniper Networks Junos OS Evolved. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A stack-based buffer overflow exists in the routing protocol daemon (rpd) when processing flow-spec updates selected for re-advertisement. An attacker acting as a configured BGP peer can trigger the overflow via a malformed flow-spec message, causing denial of service on Junos OS Evolved or remote code execution on Junos OS. The vulnerability requires the attacker to be an established BGP peer.

## Affected products

- Juniper Networks Junos OS
- Juniper Networks Junos OS Evolved

## Timeline

- 2026-10-14: disclosed

## References

- [https://supportportal.juniper.net/JSA112187](https://supportportal.juniper.net/JSA112187)

## Related threats

- [Juniper Networks Junos OS stack buffer overflow in BGP/EVPN](https://junglewise.ai/threats/cve-2026-101982-a-stack-based-buffer-overflow-vulnerability-in-the-routing)
- [Juniper Networks Junos OS stack buffer overflow in rpd](https://junglewise.ai/threats/cve-2026-101981-a-stack-based-buffer-overflow-vulnerability-in-the-routing)
- [Juniper Junos OS routing protocol daemon crash in ISO-VPN](https://junglewise.ai/threats/cve-2026-101952-an-improper-validation-of-consistency-within-input-vulnerability)
- [Juniper Networks Junos OS stack buffer overflow in BGP routing daemon](https://junglewise.ai/threats/cve-2026-102178-a-stack-based-buffer-overflow-vulnerability-in-the-bgp-routing)
- [Juniper Junos buffer overflow in SDK service process](https://junglewise.ai/threats/cve-2026-102176-a-buffer-copy-without-checking-size-of-input-classic-buffer)