Vulnerability Database

320,453

Total vulnerabilities in the database

CVE-2026-21903

A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS).

Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart. The issue was not seen when YANG packages for the specific sensors were installed.

This issue affects Junos OS: 

  • all versions before 22.4R3-S7,
  • 23.2 version before 23.2R2-S4,
  • 23.4 versions before 23.4R2.
  • Published: Jan 15, 2026
  • Updated: Jan 16, 2026
  • CVE: CVE-2026-21903
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWEs:

Software From Fixed in
juniper / junos - 22.4
juniper / junos 22.4 22.4.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 22.4-r2-s1 22.4-r2-s1.x
juniper / junos 22.4-r2-s2 22.4-r2-s2.x
juniper / junos 22.4-r3 22.4-r3.x
juniper / junos 22.4-r3-s1 22.4-r3-s1.x
juniper / junos 22.4-r3-s2 22.4-r3-s2.x
juniper / junos 22.4-r3-s3 22.4-r3-s3.x
juniper / junos 22.4-r3-s4 22.4-r3-s4.x
juniper / junos 22.4-r3-s5 22.4-r3-s5.x
juniper / junos 22.4-r3-s6 22.4-r3-s6.x
juniper / junos 23.2 23.2.x
juniper / junos 23.2-r1 23.2-r1.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 23.2-r2 23.2-r2.x
juniper / junos 23.2-r2-s1 23.2-r2-s1.x
juniper / junos 23.2-r2-s2 23.2-r2-s2.x
juniper / junos 23.2-r2-s3 23.2-r2-s3.x
juniper / junos 23.4 23.4.x
juniper / junos 23.4-r1 23.4-r1.x
juniper / junos 23.4-r1-s1 23.4-r1-s1.x
juniper / junos 23.4-r1-s2 23.4-r1-s2.x