CVE-2026-21903
Junos OS: Subscribing to telemetry sensors at scale causes all FPCs to crash
Vexday Risk Score
21Low
SSVC decision (CISA)
Track
No exploitation signal → monitor
CVSS 7.1EPSS 0.4%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado
Lifecycle
15 Jan 2026Published on NVD
Recommendation: Monitor — no exploitation signal at the moment.
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
Affected products
Juniper Networks · Junos OSWant to know if your infrastructure is exposed to this?
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